Henry Dillon, 8th Viscount Dillon

In 1689 Dillon was one of the two members of parliament for County Westmeath in the House of Commons of the Patriot Parliament.^[13] In that same year he served as Lord Lieutenant of County Roscommon.^[14]

His father, the 7th Viscount, fell in the Battle of Aughrim on 12 July 1691^[15] fighting under Saint-Ruhe against the Williamites under Ginkel. Henry succeeded as the 8th Viscount in the eyes of his Jacobite comrades, but his father had been attainted on 11 May 1691^[16] and in the eyes of the victorious Williamites there was no title or estate for him to succeed to.^[17]

Lord Dillon, as he was now, was governor of Galway for the Jacobites.^[18] Ginkel quickly marched down upon him from Aughrim and invested the town on 18 July. Dillon surrendered on the 26th on terms and marched out with his troops to Limerick.^[19] The Williamites laid siege to Limerick in August 1690. During a shelling of the town Dillon's mother Mary lost her life.^[20] The siege was lifted at the end of the month but a second siege followed in 1691 and lasted until the Williamite war in Ireland ended with the Treaty of Limerick signed on 8 October 1691.^[21]

While many of the Jacobites went into exile at the end of the war, an event called the Flight of the Wild Geese, Dillon stayed in Ireland and applied for the reversal of his attainder, which he obtained in 1694 by a judgement of the Court of the King's Bench and was confirmed by the Irish House of Lords in 1697.^[22] He, therefore, got back his title and lands.

Dillon died on 13 January 1714 in Dublin and was buried at Ballyhaunis in County Mayo.^[23] He was succeeded by his son, Richard, the 9th Viscount, who died in 1737, without male issue,^[24][c] and the title passed to his nephew Charles, his brother Arthur's son.^[25]