MacAuley and its many variants - Cawley, Gawley, Macauley, Magawley etc. - may be either Scottish or Irish in origin. They are anglicisations of two distinct Irish surnames, Mac Amhalgaidh (‘son of Auley’) and Mac Amhlaoibh ( ‘son of Auliff’). The former derives from a native personal name now obsolete, and the family bearing the surname were rulers of a territory in what is now Offaly/Westmeath. The latter derives from a Gaelic version of the common Norse name ‘Olaf’, and the family claim descent from Amhlaoibh, son of the first Maguire king of Fermanagh, who ruled at the end of the thirteenth century. They gave their name to the barony of Clanawley in that county. An entirely distinct family, the MacAuliffs of Munster, are descended from Amhlaoibh MacCarthy. In Scotland also the surname and its variants have the same two distinct origins, from the Gaelic and Norse personal names. The Scottish origin is most common in the northeast of Ulster, where a branch of the Dumbartonshire MacAuleys settled in the sixteenth century.

MacBride comes from the Irish Mac Giolla Bhride ‘son of the follower of (St) Bridget’; St Bridget was a famous abbess of Kildare , who died in 525. Also derived from the same Irish original are the surnames Kilbride, Gilbride, MacIlvreed, MacGilbride and others. The principal Irish family of the name were based in the north of Co. Donegal in Raymunterdoney, where they were very prominent in the church, a number of the family becoming bishops. A branch migrated in Co. Down in early times, where the surname remains quite numerous. In Ulster also, the name may have a Scottish origin, from the descendants of one Gillebride, progenitor of one branch of the Clan Donald. The best known contempory bearer of the surname was Sean MacBride (1904-1988), active on the Republican side in the War of Independence and after, Minister for External Affairs from 1948 to 1951, founder-member of the Amnesty International, winner of the Nobel Peace Prize in 1974, the Lenin Peace Prize in 1977 and the American Medal for Justice in 1978.

MacCabe derives from the Irish Mac Caba , from caba meaning ‘cape’ or ‘cloak’. The family are thought originally to have been a branch of the MacLeods of Harris in the Hebrides. They came to Ireland from there in the mid-fourteenth century to act as gallowglasses (mercenaries) to the O’Reillys and the O’Rourkes, the ruling families in the kingdom of Breffny, the territory now part of counties Longford and Cavan. They became completely hibernicized and adopted the customs and practices of the Irish, including internecine war; having established themselves in neighbouring Fermanagh by the fifteenth century, they continued the struggle for control with the Maguires up to the final catastrophe of the seventeenth century. The surname also became prominent in other adjoining counties, in particular Co. Monaghan.

There is a dispute as to whether McCann comes from the Irish MacAnna, ‘son of Annadh’, or Mac Cana, from cana, meaning ‘wolf cub’. At any rate, the major family of the name were known as lords of Clanbrassil, an area on the southern shores of Lough Neagh in the modern Co. Armagh, which they conquered from the O’Garveys. They appear to have been a branch of the Cineal Eoghain, the large group of families claiming descent from Eoghan, one of the sons of Niall of the Nine Hostages, the fifth century founder of the Ui Neill dynasty. The death in 1155 of one of their chiefs, Amhlaoibh Mac Cana, is recorded in the Annals of the Four Masters with praise for his chivalry, his vigour, and the fine strong drink he made from the apples in his orchard. Today, the surname is found principally in counties Armagh, Tyrone and Antrim, though it has also spread southwards into the provinces of Leinster and Connacht.

MacCarthy comes form the Irish Mac Carthaigh, from carthach, meaning ‘loving’.The original Carthach from whom the surname is taken was king of Cashel c.1040, at a time when Donncha, son of Brian Boru, was king of Munster. Carthach was part of the dynasty claiming descent from Eoghan, one of the sons of Oiloll Ollum, the semi-legendary, third-century king of Munster. The Eoghanacht, as they were known, had dominated Munster virtually unchallenged until the meteoric rise of Brian, part of the rival Dal gCais, who claimed descent from Cas, another son of Oiloll Ollum. The Eoghanacht resisted the Dal gCais fiercely, with the result that the MacCarthys and the O’Briens, with their respective allies, waged bitter, intermittent war on each other for almost a century and a half. In the middle of the twelfth century, the struggle was finally resolved with the expulsion of the MacCarthys from their homelands in the Golden Vale in Co. Tipperary. They moved south, into the historic territory of Desmond, and it is with this area, which includes the modern counties of Cork and Kerry, that they have been most strongly associated ever since. Despite their displacement, the MacCarthys retained their ability to rule. For almost five centuries they dominated much of Munster, with four distinct branches; those led by the MacCarthy Mor (‘Great MacCarthy’), nominal head of all the MacCarthys, who ruled over much of south Kerry; the Dunhallow MacCarthys, who controlled northwest Cork; MacCarthy Riabhach (‘grey’) based in Carbery in southwest Cork; and MacCarthy Muskerry, on the Cork/Kerry border. Each of these families continued resistance to Norman and English encroachment up to the seventeenth century when, like all the Gaelic aristocracy, they lost almost everything. Unlike many others, however, the line of descent of the senior branch was not lost. The current holder of the title MacCarthy Mor, recognised as such by the Chief Herald of Ireland, is Terence MacCarthy, now resident in Morocco.

MacDonagh, and its many variants, MacDonough, Donogh, Donaghy etc all derive from the Irish Mac Donnchadha, from donnchadh (often anglicised 'Donagh'), a popular first name meaning 'brown one'. The early popularity of the name meant that the surname based on it arose separately in two places; in Co Cork, where the MacDonaghs were known as 'Lords of Duhallow', and in Co Sligo, where the family were rulers in the barony of Tirreril. The Sligo MacDonaghs were in fact a branch of the MacDermotts, claiming Donagh MacDermott as their ancestor. Today the name is rare in Cork, but has become very widespread in the western province of Connacht. The best known modern bearer of the name is Donagh MacDonagh (1912-1968), the poet, dramatist and lawyer, whose most successful play, Happy as Larry, has been translated into a dozen languages.

MacDonald is extremely numerous and widespread throughout Ireland. It is commonly a confusion for MacDonnell(q.v.), and shares the same origin, coming from the Gaelic personal name Domhnall, meaning 'world mighty'. However, true MacDonalds are descendants of the Scottish clan of the name. They are one of the group of Scottish clans who claim descent from Conn of the Hundred Battles, the legendary Irish king, through Colla Uais, who colonised the Hebrides. Their name comes from Donald of Islay, one of the sons of Somhairle, Lord of Argyle. By the fifteenth century they were the most powerful clan in Scotland, controlling the entire western coast of the country. Their involvement in Ireland was continuous from the thirteenth century, when they first arrived as gallowglasses, or mercenaries; such was their fame that they were employed in virtually every local war, spreading and settling throughout the country over the following centuries. Inevitably, their main connection remained with Ulster. A secondary influx into that province of settlers bearing the name occurred in the eighteenth century, when the Highland clearances caused great forced migration from Scotland.

MacDonnell, often confused with MacDonald, comes from the Irish Mac Domhnaill, from the personal name Domhnall, a compound made up of 'world' and 'strong'. It is common and widely distributed throughout Ireland. The principal source of the name outside Ulster is in the old kingdom of Thomond, in the Clare/Limerick area, where the MacDonnells were hereditary poets to the O'Briens. Many other southern MacDonnells will in fact be descendants of MacDonald gallowglasses (see MacDonald). In Ulster, the most prominent native family were the MacDonnells of Clankelly, rulers of Fermanagh before the rise of the Maguires. Displaced by their loss of power, they settled in the north of the adjoining Co Monaghan, and remain numerous in the area. the MacDonnells of Antrim are in fact descendants of the Clan Donald. In the sixteenth century Somhairle Buidhe ('Sorley Boy') MacDonnell conquered a large part of that county and defended it tenaciously against Gaelic Irish and English intrusions. In 1620 his son, Randal MacSorley MacDonald, was created Earl of Antrim.

MacEvoy (or MacAvoy) is the phonetic anglicisation of Mac Fhiodhbhuidhe, possibly from the Irish fiodhbhadhach, 'man of the woods'. The most prominent family of the name originally held power in the barony of Moygoish in modern Co Westmeath, but migrated southwest, where they became one of the well-known 'Seven Septs of Leix', ruling over an area in the parishes of Mountrath and Raheen in Co Laois. In the early seventeenth century the most important leaders of the family were forcibly transported to Co Kerry, together with other members of the 'Seven Septs', but the surname remains numerous in the Laois/Westmeath region. In the north of the country, MacEvoy was used as an erroneous equivalent of MacGiolla Bhuidhe, 'son of the fair-haired youth', a Donegal name usually anglicised as 'McIlwee' or 'MacKelvey', and of Mac an Bheatha, 'son of life' (MacVeigh), a surname common in the Armagh/Louth region.

The surname comes from the Irish MacGiolla Mochuda, meaning 'son of the devotee of (St) Mochuda'. Its adoption was quite unusual. St Mochuda, a pet form of Carthach, meaning 'loving', was the seventh-century founder of the important monastic settlement of Lismore, in Co Waterford. He was a native of Kerry, and when his fellow Kerryman Ailinn O'Sullivan became bishop of the diocese of Lismore in the mid-thirteenth century, he initiated the practice of the O'Sullivans paying particular devotion to this saint. As a result, the practice grew up among one of the leading families of the O'Sullivans of using Giolla Mochuda as a kind of title. The first to use Mac Giolla Mochuda was Conor, who is recorded as having slain Donal O'Sullivan Beare in 1563. His family, descendants of Donal Mor O'Sullivan, the common ancestor of O'Sullivan Mor and O'Sullivan Beare (see O'Sullivan), continued to be known as 'MacGillycuddy O'Sullivan' or 'MacGillycuddy alias O'Sullivan' well into the seventeenth century, when MacGillycuddy became established as a surname in its own right. Even at this point, less-well-off members of the family continued to be known as 'O'Sullivan' for quite some time. The family controlled a large territory in the Kerry baronies of Magunihy and Dunkerron; the name of the great mountains in Dunkerron, MacGillycuddys Reeks, preserves the record of their ownership. Members of the family retained large estates in the area down to the twentieth century. Unlike many other families of the old Gaelic aristocracy, their line of descent remains clear down to the present day; the current holder of the title 'the MacGillycuddy of the Reeks', recognised as such by the Genealogical Office, is Richard Denis Wyer MacGillycuddy, now resident in France.

MacGovern is the phonetic anglicisation of Mag Shamhradhain, from a diminutive of samhradh, 'summer'. The name is closely linked with the original homeland where it first arose; in the traditional genealogies, Shamhradhan, the eleventh-century individual from whom the surname comes, was himself descended from Eochaidh, one of the O'Rourkes, who lived in the eighth century. His name was given to the area of Co Cavan where the MacGoverns held sway, the barony of Tullyhaw (Teallach Eochaidh), in the northwest of the county. The particular centres of their power were Bawnaboy, Lissanover, and Ballymagauran. This last includes an earlier anglicisation of Mag Shamhradhain, 'Magauran' or 'MacGowran', now much less common than MacGovern. From Cavan, the name has now spread throughout Connacht and Ulster, and is particularly numerous in the adjoining counties of Fermanagh and Leitrim.

MacGowan (or Magowan) is the phonetic anglicisation of the Irish Mac Gabhann and the Scottish Mac Gobhann, both meaning 'son of the smith'. In Ireland the surname originated in central Co Cavan, in what was once the ancient kingdom of Breffny, where the MacGowans were among the most powerful families. However, in Cavan itself a large majority translated their surname and became Smiths (see also the entry for that name). Outside Cavan, in the adjoining counties of Leitrim, Donegal, Sligo and Monaghan, MacGowan was the most popular English form, and the surname is most numerous in those counties today, with the largest number in Co Donegal. There, a family of MacGowans held Church lands in the parish of Inishmacsaint. Because of their prominence, a separate Donegal family based near Raphoe, the Mac Dhubhain (from a diminutive of dubh, 'black') also anglicised their name as MacGowan, adding to the numbers bearing the name in that county.

MacGrath, and its many variants: Magrath, MacGraw, Magra, comes from the Irish MacRaith, from the personal name Rath, meaning 'grace' or 'prosperity'. Two native Irish families adopted the name, one based on the borders of the modern counties of Donegal and Fermanagh, around Termon MacGrath, the other in Co Clare, where they were famous as hereditary poets to the ruling O'Brien family of Thomond. Today neither area can be claimed to have large numbers of the surname. The southern family spread eastwards, into counties Tipperary and Waterford, while the northern familys descendants are now mainly to be found in Co Tyrone, where they settled around Ardstraw after being driven from their homeland by the O'Donnells. The most remarkable bearer of the name was of this family, Meiler Magrath (1523-1622), who managed to be simultaneously, Catholic Bishop of Down and Connor and Protestant Archbishop of Cashel. His rapacity was notorious, and he held six Anglican bishoprics, four of them at the one time, as well as the income of seventy parishes. For his pains he lived to be a hundred years old.

MacGuinness, together with its variants Guinness, Magennis, MacNeice, MacCreesh and others, comes from the Irish Mac Aonghasa, from the personal name Aonghas ('Angus'), made up of aon 'one' and gus 'choice', which was borne by a famous eight-century Pictish king of Scotland, said to be a son of the Irish god Daghda, and Boinn, the goddess who gave her name to the river Boyne. The surname originated in Iveagh, in what is now Co Down, where the family displaced the O'Haugheys in the twelfth century, ruling over the region down to the seventeenth century. The centre of their power was at Rathfriland. In the sixteenth century they accepted the Reformation, but joined in the later wars against the English and were dispossessed of all their lands. The name is now common in Connacht and Leinster, as well as in its original homeland of Ulster. A southern offshoot of the family adopted the variant MacCreesh, and in Monaghan, Fermanagh and south Down that name was used as an equivalent of MacGuinness. North of the original homeland, in Co Antrim, a similar process occurred, with MacNiece or MacNeice the variant adopted there. The Guinness family who founded the famous brewery were originally from Co Down.

Along with its principal variant MacCue, MacHugh comes from the Irish Mac Aodha or Aoidhe, from the very popular personal name Aodh, meaning 'fire'. In various forms, Aodh is the root of a large number of common surnames (see Hayes, Hughes and Magee). At least three distinct families in west Ulster and Connacht adopted Mac Aodha: a branch of the O'Flahertys of Connemara in west Galway, another family based near the modern town of Tuam in north Galway and, in Fermanagh, a family who claim descent from Aodh, a grandson of Donn Carrach Maguire, the first Maguire ruler of the county. Today the surname is most numerous in Co Donegal and in north Connacht, though it is also common in Leinster. In parts of Ulster - Fermanagh in particular - it was considered interchangeable with Magee until quite recently.

MacKenna is the English form of the Irish surname Mac Cionath. The Mac Cionath were originally based in Meath, but in early tomes were brought north into Clogher as hired fighters by the rulers of that territory, and quickly became lords in their own right of Truagh, a territory on the borders on the modern counties off Tyrone and Monaghan. Their power endured down to the seventeenth century, their last chief being Patrick McKenna, who died near Emyvale, Co Monaghan, in 1616. The surname is still very numerous in the area of the original homeland, but over the centuries has spread throughout the country. Juan MacKenna (1771-1814) was born at Clogher in Co Tyrone and was a general under Bernado O'Higgins in the fight for Chilean liberation.

MacKeon has a wide range of synonyms and variants, including Keon, MacKeown, MacGeown, MacOwen and, in Ulster, MacEwan, MacCune, MacKone, Magowen and, occasionally, Johnson or Johnstone. The reason lies in the Irish and Scottish original of the name, Mac Eoin, 'son of Eoin (John)', which arose independently in a number of areas. In Ireland the principal areas of origin were in the Kiltartan region of Co Galway, at Creggan and Derrynoone in Co Armagh and in Sligo/Leitrim in north Connacht. This last family were the most prominent historically, and it is thought that the Galway family were an offshoot. In Co Antrim, the surname is almost entirely of Scottish origin, and derives from Eoin Bissett, who came to the Glens of Antril from Scotland in the thirteenth century. The form MacKeown is largely confined to northeast Ulster, while MacKeon is most common in Connacht and west Ulster. As so often with variants in spelling, however, no absolute rules are possible.

MacLoughlin is the form of the name most frequent in Connacht and Leinster, while McLaughlin is most common in Ulster, particularly in counties Antrim, Donegal and Derry. Both forms derive from the Irish and Scottish Mac Lochlainn, from the personal name Lochlann, from loch, 'lake' or 'fjord', and lann, meaning 'land'. It was a Gaelic name used for Scandinavia, and was applied to the Viking settlers of the early Middle Ages, and became a popular name in its own right. the surname containing it has at least three origins in Ireland: in Co Clare, where the MacLoughlins claimed descent from Lochlann, a tenth-century lord in the barony of Corcomroe; in the Inishowen peninsula of Co Donegal, where the family were among the most powerful in Ulster down to the late middle ages, and in Co Meath, where the descendants of the tenth-century high king, Maolseachlann
(or Malachy II), were first known as O'Melaghlin, later corrupted to MacLoughlin.

MacMahon (or MacMahon) comes from the Irish Mac Mathghamha or, in the modern version, Mac Mathuna, from mathghamhqain, meaning 'bear'. The surname arose separately in two areas, in west Clare and in Co Monaghan. In the former, the MacMahons were part of the great tribal grouping, the Dal gCais, and claim descent from Mahon O'Brien, grandson of Brian Boru. The last Chief of the Name was killed at the battle of Kinsale in 1602. The Ulster MacMahons were based in the barony of Truagh in the north of Co Monaghan, and ruled the kingdom of Oriel between the thirteenth and sixteenth centuries. Their last chief, Hugh MacMahon, was beheaded by the English in 1641. Today, although widespread throughout Ireland, MacMahon remains most common in the two ancestral homelands of Clare and Monaghan. After the defeats of the native Irish in the seventeenth century, many of the Clare MacMahons emigrated to serve in the Irish Brigade of the French Army. One of their descendants, Patrick MacMahon (1808-93), became President and Marshal of France.

MacManus is the anglicisation of the Irish Mac Maghnais, from the popular Norse personal name Magnus, derived ultimately from the Latin magnus, 'great'. Although the Viking settlers are responsible for the introduction of Magnus as a personal name, the surname it gave rise to is entirely Irish. It came into being in two distinct areas: in Co Roscommon, where the family claim descent from Maghnais, son of the twelfth-century High King, Turlough O'Connor; and in Co Fermanagh, where the original ancestor was Maghnuis Maguire, son of the chieftain Donn Mor maguire. In Fermanagh they were second in power only to the Maguires themselves, and from their base on the island of Ballymaguire (now Belleisle) on Lough Erne controlled the shipping and fishing of the lake. Cathal Og MacManus (1439-1498), chief of the name, dean of Lough Erne and vicar-general of the diocese of Clogher, was responsible for the compilation of the Annals of Ulster. Today the surname is most common by far in its original homelands, and especially in Co Fermanagh.

MacNally, MacAnally and Nally all share the same Irish origins, in the two Irish names mac an Fhailghigh, 'son of the poor man', and Mac Con Uladh, 'son of the hound of Ulster'. As might be expected, the latter name is almost entirely confined to Ulster, in particular to that part of the modern province originally called Ulaidh, the southeast, in particular counties Armagh and Monaghan. Today, the anglicised versions of the name remain very common in these counties, with the 'Mac-' forms in the majority. Outside Ulster, the principal origin of the name is in northwest Connacht, in counties Roscommon and Mayo, where it is said that the name as adopted by the descendants of the Norman settlers. The most common form in these counties is the simple 'Nally'. One extremely prominent bearer of the name was the Reverend David Rice MacAnally (1810-1895), a sheriff and Methodist preacher who is said to have weighed more than 360lbs (160kg).

MacNamara comes from the Irish Mac Conmara, 'son of the hound of the sea'. The surname arose in Co Clare, where the family were part of the famous Dal gCais tribal grouping. They were second only to the O'Briens, to whom they were hereditary marshals. From relatively minor beginnings they grew in power to become rulers of the territory of Clancullen, a territory including a large part of what is now east Clare, where they held sway for almost six centuries, down to the final defeat of Gaelic culture in the seventeenth century. Today, the surname is widespread throughout Ireland, but the largest concentration remains in the area of the original homeland, in counties Clare and Limerick. Brinsley MacNamara (1890-1963), the novelist and playwright, and the most famous modern bearer of the surname, was in fact John Weldon. He adopted the pseudonym as protection; his famous work, The Valley of the Squinting Windows, was highly critical of Irish rural life.

Madden is the anglicised version of the Irish O Madaidhin, from a diminutive of madadh, meaning 'hound'. in the early times, the family were part of the Ui Maine tribal grouping based in east Co Galway, and ruled the area up to late Middle Ages. Even today, the surname is most numerous by far in east Galway. A branch of the family moved south to the Clare/Limerick region in early times, and anglicised their name as 'Madison', and this separate surname is also still most strongly associated with its original homeland. The most famous bearer of the name was Richard Robert Madden (1798-1886), doctor, traveller, historian and fervent opponent of the slave trade.

Magee, and its variants McGee, MacGee etc, comes from the Gaelic Mac or Mag Aodha, from Aodh (anglicised 'Hugh'), a very popular personal name meaning 'fire', which also gave rise to a large number of other surnames, including hays, Hughes, McHugh, and McCoy. The form 'Magee' reflects the pronunciation of Ulster and Scottish Gaelic, with 'Mag-' most common in the east of the province, and 'Mac-' in the west; Ulster is the area where the name is most common by far. It can be of either Scottish or Irish origin. Three Irish families of the name are recorded: in the area now on the borders of counties Donegal and Tyrone, in the territory around Islandmagee on the coast of Antrim, and in Fermanagh, where they descend from Aodh, great-grandson of Donn Carrach maguire, the first Maguire ruler of that region. The remainder of the Ulster Magees are descended from seventeenth-century settlers from Scotland, where the surname is most common in Dumfries, in Ayshire and in Galloway. In Co Cavan, Mag Aodha has also sometimes, strangely been anglicised as 'Wynne', from a mistaken resemblance to gaoth, 'wind'.

Maguire, with its variants MacGuire, McGwire etc, comes from the Irish Mag Uidhir, meaning 'son of the brown(-haired) one'. The surname is now extremely common throughout Ireland, with particular concentrations in Cavan, Monaghan and Fermanagh; in Fermanagh it is the single most numerous name in the county. The reason is not far to seek. From the time of their first firm establishment, in Lisnaskea around the start of the thirteenth century, all the associations of the family have been with Fermanagh. By the start of the fourteenth century, the chief of the family, Donn Carrach Maguire, was ruler of the entire county, and for the following three hundred year there were no fewer than fifteen Maguire chieftains of the territory. By the year 1600, Co Fermanagh quite simply belonged to the family. As for so many other Gaelic families, the seventeenth century was catastrophic for the Maguires. First, a junior branch, based around the area of the modern town of Enniskillen, were dispossessed and their lands parcelled out in the Plantation of Ulster. Then, as a result of their participation in the rebellions of the Cromwellian and Williamite periods, virtually all the remainder of their possessions were taken. Unlike the bulk of the native Irish aristocracy, the descent of the Maguires has remained intact. The current bearer of the title ' Maguire of Fermanagh' is Terence Maguire, officially recognised by the Chief Herald of Ireland in 1991 as the senior male descendant of the last inaugurated Maguire chief.

Maher, and its principal variant Meagher, are the anglicised versions of the Irish O Meachair, from meachar, meaning 'hospitable'. The surname originated in Ikerrin near the modern town of Roscrea in north Tipperary, where the family retained their traditional lands right up to the modern period. The name remains very strongly linked to the traditional homeland, with the bulk of present-day Mahers living or originating in Co Tipperary. Thomas Francis Meagher (1823-1867) was one of the founders of the revolutionary 'Young Ireland' movement. Transported to Australia. he managed to escape to the U.S. where he became Brigadier-General of the Irish Brigade of the Union Army during the Civil War, and was later Governor of Montana.

Malone is the anglicised form of the Irish O Maoil Eoin, meaning 'descendant of a devotee of (St) John', maol being the Irish for 'bald' and referring to the distinctive tonsure sported by Irish monks. The family was an offshoot of the O'Connors of Connacht, and lived up to the ecclesiastical origin of their surname in their long connection with the famous Abbey of Clonmacnoise, with a line of Malone bishops and abbots. Today they are largely dispersed from this area, and the largest concentrations are to be found in counties Clare and Wexford. The most famous bearer of the name was Edmund Malone (1741-1812), a friend of Samuel Johnson, James Boswell and Edmund Burke amongst others, whose complete edition of the works of Shakespeare remained standard for almost a century.

martin is an extremely common name throughout the English-speaking world and,in its many variant forms, throughout Europe; its popularity is largely due to the widespread fame of the fourth-century saint, martin of Tours. In Ireland, the surname may be of English, Scottish or native Irish origin. The best-known Martins, powerful in west Galway and Galway city for centuries, were of English extraction, having arrived with the Normans. The largest number of Irish origin stem from the Mac Giolla Mhartain, 'son of the follower of (St) Martin', also anglicised as 'Gilmartin', who were a branch of the O'Neills. They originally held territory in the barony of Clogher in Co Tyrone, but were displaced westwards into the adjoining counties of Sligo and Leitrim, where they are most numerous today. The Scottish origin of the name is similar, from an anglicisation of Scots Gaelic Mac Gille Mhartainn. Richard ('Humanity Dick') Martin (1754-1834), of the Galway family, was one of the founders of the Royal Society for the Prevention of Cruelty to Animals.

Meehan, along with its variant Meighan, comes from the Irish O Miadhachain, from miadhach, meaning 'honourable'. Historically, the most notable family of the name were an offshoot of the MacCarthys of the kingdom of Desmond in south Munster. However, as early as the eleventh century they migrated north to Co Leitrim. From there they spread slowly into the adjoining counties, and are now numerous throughout east Connacht, Donegal and Fermanagh. This family preserved a sixth-century manuscript of St Molaise of Devenish from generation to generation for more than a thousand years; it is now held in the National Museum in Dublin. A separate family appears to have adopted the surname in the late Clare/Galway region, where the name is also numerous. In Monaghan, and there alone, it has been anglicised as 'Meegan'.

Molloy, along with Mulloy and O'Molloy, is the anglicised version of a number of distinct Irish names. The O Maolmhuaidh, from maolmhuadh meaning 'proud chieftain', were part of the southern Ui Neill, the southern branch of the large tribal grouping claiming descent from Niall of the Nine Hostages, the fifth-century king who supposedly kidnapped St patrick to Ireland. they held power over a large part of what is now Co Offaly, where the surname is still very common. A second family were the O Maoil Aodha, 'descendant of the devoteee of (St) Aodh', from maol, literally 'bald', a reference to the distinctive tonsure sported by early Irish monks. As well as Molloy, this surname has also been anglicised as 'Miley' and 'Millea'. The name arose in east Connacht, in the Roscommon/east Galway region, and remains numerous there today.

Moloney, along with its variants Mullowney and Maloney, is the English version of O Maol Dhomhnaigh, meaning 'descendant of the servant of the church', Maol means 'bald', and refers to the distinctive tonsure common in the early Irish Church, while domhnach means 'Sunday', and was used by extension to refer to the place of worship on that day. the surname arose in Co Clare, near the modern town of Tulla, and remains extremely common there, as well as in the adjoining counties of Limerick and Tipperary. Mullowney has also sometimes been used as the anglicisation of the Ulster surname MacGiolla Dhomhnaigh, meaning 'son of the servant of the church', usually anglicised as 'Downey' or 'MacEldowney', which is found principally in counties Antrim and Derry. Both of these names were sometimes used for the illegitimate offspring of clergymen.

Monaghan is the English version of the Irish O Manachain, from a diminutive of manach, meaning 'monk', and some of the family adopted the semi-translation 'Monks'. Most of the surname in Ireland descend from one Manachain, a chieftain who lived in Connacht in the ninth century, and it is with that province, specifically with east Roscommon close to the river Shannon, that the family are most closely linked. Up to the end of the thirteenth century they were rulers of this area, known as 'the Three Tuathas'. The name has spread from the original homeland, and is now common also in Mayo and Galway. In Co Fermanagh, where the name is also numerous, the family are thought to be part of the original inhabitants of the area, the Fir Manach, from whom the county gets its name. Their base was in the district of Lurg. From here the name has now also scattered in the adjoining counties of Monaghan and Derry.

Mooney comes from the Irish O Maonaigh, which may derive from the Old Irish maonach, meaning 'dumb', or from maoineach, meaning 'wealthy'. It arose as a surname independently in each of the four provinces. In Ulster, it was the name of a family based in the parish of Ardara, in Co Donegal. The Connacht family were located in the parish of Easky in the barony of Tireragh in Co Sligo, where 'Meeny' is often the English version used. In Munster, reflecting the different pronunciation, the English is often 'Mainey'. But the most notable family arose in Leinster, in the modern Co Offaly, where they were concentrated around the parish of Lemanaghan. Their descendants are by far the most numerous today, although the name has now spread throughout Ireland.

Moore is today one of the most common surnames in Ireland, among the top twenty. It may be of English, Irish, Welsh or Scottish origin. In England the name may derive either from someone who lived near a moor or from a nickname for someone of dark complexion, from 'moor', meaning Negro. This is frequently also the ultimate origin of the name in Scotland and Wales, where it is often rendered 'Muir', although in places it is thought to come from mor, 'big'. the Irish origin of Moore is O Mordha, also anglicised O'More, from mordha, meaning 'stately' or 'noble'. The principal family of definite native Irish origin were of Co Laois, where they were the leading sept of the famous 'Seven Septs of Laois', whose resistance to the English led to the forced resettlement of the most prominent individuals in Co Kerry. At this point, it is virtually impossible to say in any single case which of the various origins of the surname is the most accurate.

Moran is the anglicisation of two distinct Irish names, O Morain, from mor, meaning 'big', and O Mughrain, whose origins remain unclear. The former arose in Co Mayo, near the modern town of Ballina, where the eponymous ancestor Moran held power. The latter family were part of the Ui Maine tribal grouping. Their two branches were based around Criffon in Co Galway, and the modern village of Ballintober in north Roscommon. Today, as might be expected, the vast majority of Morans are of Connacht origin. One of the most famous bearers of the name was Michael Moran (1794-1856), better known by his nickname of 'Zozimus', who was blinded in infancy and made his living on the streets of Dublin with his recitations and ballads. A monument to him stands in Glasnevin cemetary.

In origin Morgan is Welsh, deriving from an Old Welsh name meaning 'sea-bright'. The majority of Irish Morgans are almost certainly of Welsh or Welsh Norman stock. The surname is common in Connacht and leinster, but most numerous in Ulster. Here, it is possible that some are descended from the Clann Morgunn of Sutherland in Scotland, or from a separate family based in Aberdeenshire. There is also a Gaelic Irish family in Ulster, the O Murchain, who were based in Co Monaghan, whose surname was anglicised Morgan. The writer Lady Sydney Morgan (1783-1859) had immense success with her books on the politics and society of France and Italy, and her salon in Kildare Street was the centre of Dublin literary life.

Moriarty is the English version of the Irish O Muircheartaigh, made up of muir, 'sea', and ceardach, 'skilled', thus 'one skilled in the ways of the sea'. The name is undoubtedly linked to their original homeland, on both sides of Castlemaine harbour in south Co Kerry. The continuity of their association with the area is remarkable, even by Irish standards. They have lived in the area since the surname came into being in the eleventh century, and ninety per cent of present births of the surname are still in Co Kerry. This continuity is all the more tenacious for the fact that they had lost virtually all their power in the area by the fourteenth century. David Moriaty (1814-1877) was a Catholic bishop of Kerry notorious for his vehement denunciations of all opposition to the British government, saying of the Fenian leaders 'eternity is not long enough nor Hell not enough for such miscreants'. O Muircheartaigh was also a surname found in Meath and the midlands, but in these areas it has been anglicised as 'Murtagh'.

Morris is a common surname throughout the British Isles, and in virtually all cases is derived, directly or indirectly, from the personal name Maurice, which comes from the Latin Maurus, meaning 'moorish' (see Moore). A large number of those bearing the name in Ireland, where the name is most frequent in Leinster, with significant numbers also in Ulster and Connacht, will be of English, Scottish or Welsh origin. There was also an Irish family, the O Muirghease, (from muir, 'sea' and gease, 'taboo') part of the Ui Fiachrach tribal grouping in Co Sligo, whose surname was originally anglicised Morrissey and later shortened to Morris. O Muirghease was also the surname of a family in Co Fermanagh who anglicised their name to Morris. The most prominent family of the name, one of the famous 'Tribes of Galway', were of Norman extraction and originally known as de Marreis.

Mullan, together with its variants Mullin, Mullen, Mullane and Mullins, can have a variety of distinct origins. First, it may be the anglicisation of the Irish name O Maolain, from a diminutive of maol, 'bald' or 'tonsured', which arose separately in a number of areas. The Co Galway family of the name claim descent from Maolan, himself descended from a king of Connacht. A different family of the same name were based in a district of Co Derry, and were followers of the O'Cahans (see Kane). In Co Monaghan a family of the name arose around the modern town of Clones; their name has also been anglicised as Mollins. Yet another family hails from south Co Cork, where the name is frequently given as Mullins. As well as all of these, many MacMillans, Scottish settlers in Ulster in the seventeenth century, adopted MacMullan, often shortened to Mullan. There is also an English name Mullins, from the Middle English miln, 'mill', and a good number of Irish bearers of the name are undoubtedly of this origin.

Mulligan comes from the Irish O Maolagain, from a diminutive of maol, literally meaning 'bald' and referring to the distinctive tonsure of the early Irish monks. In the early Middle Ages they were rulers of the territory of Tir MacCarthain, in the baronies of Boylagh and Raphoe in Co Donegal, and held power down to the plantation of the seventeenth century. After this they were dispersed, and migrated south to Mayo and east to counties Fermanagh and Monaghan. Some members of the family anglicised their surname, by quasi-translation, to Baldwin. Milligan is another common variant, found most frequently in counties Antrim, Down and Derry. Hercules Mulligan (1740-1825), born in Coleraine, acted as a secret agent for George Washington during the War of Independence.

Murphy is the anglicised version of two Irish surnames, O Murchadha and Mac Murchadha, both derived from the popular early Irish personal name Murchadh, meaning 'sea-warrior'. Mac Murchadha ('son of Murchadh') is exclusive to Ulster, where the family were part of the Cineal Eoghain, the tribal grouping claiming descent from Eoghan, himself a son of the fifth century founder of the Ui Neill dynasty, Niall of the Nine Hostages, who was reputedly responsible for the kidnapping of St Patrick to Ireland. These Ulster Murphys (or MacMurphys) were originally based in present-day Co Tyrone, in the area known as Muintir Birn, but were driven out by the O'Neills and settled in south Armagh, where they were subjects of the O'Neills of the Fews. In Ulster today, Murphy remains most numerous in Co Armagh, though it is also to be found in great numbers in Fermanagh and Monaghan. Elsewhere in Ireland, O Murchadha (descendant of Murchadh) is the original Irish. This arose separately in at least three distinct areas; in Cork, Roscommon and Wexford. The most prominent of these were the Wexford Ui Murchadha. These took their surname from Murchadh or Murrough, grandfather of Dermot MacMurrough, King of Leinster, and thus share their origin not only with the MacMurroughs but also with the Kinsellas, the Kavanaghs and the MacDavy Mores. Their territory lay in the barony of Ballaghkeen in Wexford, and was formerly known as Hy Felimy, from Felim, one of the sons of Eanna Cinsealaigh, the semi-legendary, fourth-century ruler of Leinster. Their chief seats in this area were at Morriscastle ('O Murchu's Castle'), Toberlamina, Oulart and Oularteigh. The last chief of the name to be elected by the old Gaelic method of tanistry was Murtagh,who in 1461 was granted the right to use English law, this entitling him to pass on his possessions to his direct descendants. The arrangement lasted only until the late sixteenth century, when Donal Mor O'Morchoe (as the name was then anglicised) was overthrown, and virtually all his territory confiscated; most of his followers were scattered and settled in the surrounding counties, in Kilkenny and Carlow particularly. One branch, however, based at Oularteigh, did manage to retain their lands, and their succession continues unbroken down to the present. David O'Morchoe (this version of the name was adopted by deed poll by his grandfather in 1895) is the current Chief of the Name, recognised as such by the Chief Herald of Ireland.

Murray is an extremely common surname throughout Ireland, among the twenty most numerous.It can be of Scottish or Irish origin. The Scottish surname, Murray or MacMurray, derives from Moray in the northeast of the country, a name which originally meant 'settlement by the sea'. The earliest recorded ancestor of this family was one Hugh Freskin, a Flemish settler who obtained large grants of land in Morayshire in 1130; his descendants took their name from his property. Many in Ireland, in Ulster particularly, are of this connection. In Ireland the surname came from O Muireachaidh, 'descendent of the seaman'. The most prominent family of the name were based in the south Roscommon/east Galway region, and were part of the Ui Maine tribal grouping. As well as these, however, a separate family of the same name are recorded in Cork, in the barony of Carbery, and Mac Muireachaidh, anglicised as Murray and MacMorrow, is found in Co Leitrim and north Co Down. In addition Mac Giolla Mhuire, 'son of the servant of Mary', another Co Down name, has sometimes been anglicised as Murray, as well as the more obvious MacIlmurray and Gilmore.