Alexander MacDonnell, 3rd Earl of Antrim PC (Ire) (1615 – June 1699) was a Catholic peer and military commander in Ireland.
The MacDonnels descended from the twelfth-century Scottish warlord Somerled and from Alexander MacDonald, 5th of Dunnyveg, a Scottish-Irish magnate, who was driven out of Scotland by James IV and fled to Ulster where the family was already established through marriages and owned much land in the north-eastern corner of Ireland facing Scotland across the North Channel.
His Scottish lands were taken over by the rival Clan Campbell, although the MacDonalds continued to live there and looked towards the MacDonnell family for leadership.
Recovering his Scottish lands remained an objective that his father pursued all his life without ever making any progress toward it.
Alexander's mother was described as "of good cheerful aspect, freckled, not tall but strong, well set, and acquainted with the English tongue.
However, her father had left Ireland in the Flight of the Earls in 1607 and was then attainted by the Irish Parliament, losing his title and lands.
[20] He returned to Ireland just before the outbreak of the Irish Rebellion of 1641, in which he sided with the rebels and commanded a regiment in what would soon become the Confederate Ulster army.
[21] In November 1643 the Supreme Council appointed seven delegates, Muskerry, Alexander MacDonnell, Robert Talbot, Nicholas Plunkett, Dermot O'Brien, Geoffrey Browne, and Richard Martin,[22] to submit grievances to the king [23] and negotiate a peace treaty.
[26] He demanded free exercise of the Catholic religion, independence of the Irish Parliament from that of England, and oblivion for their rebellion.
[27][28] However, the arrival of a competing Irish Protestant delegation on 17 April 1644 prevented the King from making such concessions and no peace treaty was signed.
Unlike his brother Randal, Alexander respected and adhered to the peace between the Confederates and the Royalists negotiated by Ormond in 1648 and urged for a conciliatory approach.
Alexander and Helena had two children (the birth order is unknown): On 3 February 1683 his only brother, Randal, died childless.
At that time Tyrconnell's remodelling of the Irish army had advanced so far that few units still had significant numbers of Protestant soldiers.
Tyrconnell considered this unit unreliable and on 23 November he ordered Mountjoy to march to Dublin, supposedly for embarking to England.
When Antrim finally got his troops on the way, he met Colonel George Philips, a Protestant, at Newtown Limavady, who immediately sent a messenger to Derry to warn the city.
On 21 December Mountjoy reached Derry and struck a deal with the city, according to which two of his companies, consisting entirely of Protestant soldiers, would be let into town.
[51] Alexander MacDonnell, 3rd Earl of Antrim, died in June 1699 and was buried at Holywell, Flintshire, Wales.