Taaffe, Nicholas (1677–1769), 6th Viscount Taaffe general , in the Austrian service, was born at Crean's Castle, Co. Sligo, son of Francis Taaffe, a grandson of John, 1st Viscount Taaffe, and his wife Anne, daughter of John Crean of Crean's Castle. His family had strong Jacobite connections and he was sent abroad as a young boy for his education, spending some time at college in Lorraine. On completing his education, he was appointed as chancellor to Duke Leopold of Lorraine, whose son married Maria Theresa of Austria and became Emperor Francis I (1745–65).
In 1726 Taaffe was commissioned as a captain in the Austrian service, continuing a family tradition of service in that army. He served in the cavalry regiment of Count Hautois, and in 1729 was promoted to lieutenant-colonel. Promoted to full colonel in January 1732, he commanded the Lanthieri cuirassier regiment during the war of the Polish succession (1733–5) and greatly distinguished himself in the Austro–Turkish war (1737–9). In November 1738 his cousin Theobald, 4th earl of Carlingford and 5th Viscount Taaffe, died without a male heir, and he succeeded to the family's Irish titles and estates. A protestant relative, Robert Sutton, realised that under the terms of the penal laws he was eligible to claim the Taaffe estates, and a long legal battle ensued. The estates were eventually sold to John Petty Fitzmaurice, later earl of Shelburne, and Taaffe was only allocated one-third of the proceeds, around £25,000.
In February 1739 he was promoted to major-general in recognition of his recent services against the Turks. Summoned to the Irish parliament in December 1741, he did not attempt to take his seat (as a catholic he was barred) and he had in any case by this time acquired estates in Silesia and Bohemia. He was popular among his tenants and introduced the potato on his estates. Promoted to major-general in July 1752, he played a significant role during the Seven Years' War (1756–63), and at the battle of Kolin (1757) helped to rally the Austrian heavy cavalry, which was in disarray. In 1758 he was created a count of the Holy Roman Empire.
He was deeply concerned with the plight of catholics in Ireland and travelled to England and Ireland on several occasions in an effort to convince politicians that a relaxation in the penal laws was necessary. Taaffe was a dignified and commanding figure, and his high position at the Austrian court ensured him an audience at the highest political levels. He published an articulate argument against the penal laws: Observations on affairs in Ireland from the settlement in 1691 to the present time (Dublin and London, 1766). He died at his seat, Ellischau Castle in Bohemia, on 30 December 1769, shortly after the death of his wife, which had affected him deeply.
He married (October 1729) Maria Anna (Mariana) von Spindler (d. 21 November 1769), daughter of Johann-Philipp, 1st Count von Spindler. They had two sons: the elder, John Taaffe (1733–65), served as imperial chamberlain (1759), imperial chancellor (1760), and imperial ambassador to Portugal (1764–5); the younger, Francis Taaffe (1737–1803), was also a general in the Austrian army and a count of the Holy Roman Empire. Nicholas's grandson, Rodolphus Taaffe (1762–1830), succeeded him as 7th Viscount Taaffe.