Roman Catholic Church teaching says it is a mortal sin to take the life of another except in self-defence or in defence of one's own country. From 1589 on wards a mercenary exclusively meant a soldier serving in a foreign army, killing for the sake of gain.
A gallowglass - one of a particular class of soldier or retainer formerly maintained by Irish chiefs - was a mercenary. The name derived from galloglach, gall, a foreigner, and oglach, youth, servant. One of the most famous of the Scottish galloglass families was Mac Suibhne, anglicised Mac Sweeney, and Sweeney. This family was descended from Suibhne, a Scottish chieftain who flourished around 1200 in Argyll.
In the Irish language the letter `s' is usually the initial letter of a positive word, whereas `d' is the initial letter of a negative word - sonas, `happiness, good-luck', as against donas, `ill-luck, misfortune'; saibhir, `rich, wealthy', and daibhir, `poor, indigent', and where the word suibhne denotes `pleasant', the word duibhne denotes `disagreeable'. From the first came the surname Mac Suibhne, and from the latter derived the surname O Duibhne, anglicised (O) Deeny.
Mac Suibhne is given as the original Mawhinney, a name numerous in Ulster, betimes rendered MacQueen and MacQueenie. From the 14th to the 17th centuries the Mac Sweeney sept of Tirconnell, chiefly as mercenaries in the pay of O'Donnell, played an important part in the military history of Ulster.
With the native Irish, they suffered after the 17th century wars and many went into exile, becoming distinguished soldiers in the Irish brigades of the continent (Ulster Surnames: Robert Bell). This Scottish galloglass family established three septs in Donegal and a branch in Cork.
Those of Donegal were the Mac Suibhne of Banagh, Mac Suibhne of Fanad and Mac Suibhne na dTuath. This latter was mistakenly believed to be Mac Suibhne na dTua (of the battle-axes). Fanad names neither a townland, a parish nor a barony, but survives as the name of the distinct area west of Lough Swilly, deriving its name from the Irish Fanaid, meaning `sloping ground'.
Mac Suibhne, in a variety of anglicised forms, is found in some 236 fiants in The Irish Fiants of the Tudor Sovereigns 1521-1603. It was most numerous in Co Cork, followed by Donegal, Sligo, Galway, Clare and Tipperary.
Much mentioned was Sir Mulmory/Miles (from the Irish Maolmuire), M'Swyne of Toa (na dTuath) in Tyrconnell province of Ulster, Knt., of the town of Bealfearste. Many of these fiants concerned the surrender and regrant of his Donegal lands, which included the islands of Torrey and Dowagh.
"To hold for ever, by the service of a 20th part of a knight's fee, and the services of five horsemen and 10 footmen, at every general hosting, and 15 beeves yearly . . ."
The Civil Survey 1654-58 lists the McSwynes of Donegal as Irish Protestants, one being Mary Ni Swyne, Coulderry, Magheridrummon. The Census of Ireland 1659 lists Mac Sweeney among the principal Irish names of two baronies each of Sligo and Clare, and one each in Donegal, Cork and Tipperary. Tituladoes, or leading men of a locality, were listed in Cork, Clare, Donegal, Tipperary, and Kerry.
Persons bearing this surname, spelt M'Sweeney and Sweeney, and occasionally Swin(e)y, listed in Owners of Land of One Acre and Upwards (1876), were fairly equally distributed through all four provinces. The largest number in any one county was in Cork, where those with the larger holdings retained the Mac, while those located around Clonakilty, Bandon and Commons, on smaller holdings were plain Sweeneys. The 1,673 Co Galway acres, the property of Bernard Sweeney, Caher, Castlerea, was the largest, followed by the 807 acres in the same county, the property of Bryan M'Sweeney, London. There was a single Donegal holding, the 678 acres of John H. Swiney, Ramelton.
Current telephone directories have 1,770 Sweeney entries, most strongly along the west, followed by Leinster. Surprisingly there are only 90 in the Cork area. Those with `Mac' number 105, of which 57 are in the Cork area. There are three Mac Suibhne and two Ni Shuibhne entries.
Unquestionably, the best-known bearer of this surname was Terence MacSwiney (18791920), republican, politician and writer. When arrested under the Defence of the Realm Act, on August 19th, 1920, MacSwiney embarked on a hunger-strike, dying 74 days later in Britain's Brixton Prison.