Dictionary of National Biography, 1885-1900/O'Shaughnessy, William (1674-1744)
O'SHAUGHNESSY, WILLIAM (1674–1744), major-general in the French service, son of Roger O'Shaughnessy and his wife Helen, daughter of Conor MacDonogh O'Brien of Ballynee, co. Meath, was born in 1674, and, on the death of his father in July 1690, became the head of the O'Shaughnessys of Gort, co. Galway. The year previous, when a boy of fifteen, he became captain of foot and afterwards acting-colonel in King James's army. He went to France early in 1690 with the regiment of the Irish brigade commanded by Daniel O'Brien, afterwards third Viscount Clare [see O'Brien, Daniel, first Viscount], in which he was appointed captain by Louis XIV on 10 July 1691. He served in Italy in 1692; was present at the battle of Marsaglia, in Piedmont, in 1693; and in 1696 witnessed the close of the operations at the back of the Alps by the siege of Valenza, where he became commandant of the third battalion of his regiment, and was appointed to the army of the Meuse. When the 2nd and 3rd battalions of Clare were 'reformed' in 1698, he was appointed captain of the grenadiers of the battalion which was kept up from 1 April 1698. With his regiment, one of the most famous of the Irish brigade, he served in Germany in the campaigns of 1701–2; was present at the reduction of Kehl and the first battle of Hochstedt in 1703; and at the great battle there, otherwise known as Blenheim, the year after. In 1705 he served with the army of the Moselle. In 1706 he fought at Ramillies, and became major of Clare on 4 July, upon the death of Major John O Carroll, and lieutenant-colonel on 12 Sept. He was with his regiment in Flanders in 1707; at Oudenarde in 1708; at Malplaquet in 1709; at the defence of the lines of Arleux, Denain, Douay, Bouchain, and Quesnoy in 1710–12. Subsequently he served in the campaigns in Germany, including the sieges of Landau and Freiberg. He became a brigadier-general on 3 April 1721; was employed with the army of the Rhine in 1733, and was present at the siege of Kehl; served with the army of the Rhine in the campaigns of 1734–5, attaining the rank of major-general (marechal-de-camp) 1 Aug. 1734; served with the army in Flanders in 1742; commanded at Cambray during the campaign of 1743; and on 1 Nov. of that year was appointed to the command at Gravelines, where he died, without issue, on 2 Jan. 1744, aged 70, being then the oldest Irish major-general in the French service.
[O'Callaghan's Irish Brigades in the Service of France, Glasgow, 1870, pp. 26–7, 38–46, 336–7.]