Lieutenant-General James FitzGerald, 1st Duke of Leinster, PC (Ire), Irish nobleman, soldier and politician, is born on May 29, 1722. He is styled Lord Offaly until 1744 and known as The Earl of Kildare between 1744 and 1761 and as The Marquess of Kildare between 1761 and 1766.
FitzGerald is a member of the Irish House of Commons for Athy from 1741 before succeeding his father as 20th Earl of Kildare in 1744. He is sworn of the Privy Council of Ireland in 1746 and in 1747, on the occasion of his marriage, he is created Viscount Leinster, of Taplow in the County of Buckingham, in the Peerage of Great Britain, and takes his seat in the British House of Lords that same year. From 1749 to 1755 he is one of the leaders of the Popular Party in Ireland, and serves as the country’s Master-General of the Ordnance between 1758 and 1766, becoming Colonel of the Royal Irish Artillery in 1760. He is promoted to Major-General in 1761 and to Lieutenant-General in 1770.
In 1761 FitzGerald is created Earl of Offaly and Marquess of Kildare in the Peerage of Ireland and in 1766 he is further honoured when he is made Duke of Leinster, becoming by this time the Premier Duke, Marquess and Earl in the Peerage of Ireland.
FitzGerald marries the 15-year-old Lady Emily Lennox, daughter of Charles Lennox, 2nd Duke of Richmond and one of the famous Lennox sisters, in London on February 7, 1747. She descends from King Charles II and is therefore a distant fifth cousin of King George III (both of them are descended from King James VI and I). The couple has nineteen children.
FitzGerald dies at the age of 51 at Leinster House, Dublin, on November 19, 1773, and is buried in the city’s Christ Church Cathedral. He is succeeded by his second (but eldest surviving) son, William, Marquess of Kildare. The Duchess of Leinster causes a minor sensation by marrying her lover William Ogilvie in 1774, but continues to be known as The Dowager Duchess of Leinster. She has a further three children by him. She dies in London at the age of 82 in March 1814.
(Pictured: James FitzGerald, 1st Duke of Leinster, by Joshua Reynolds, 1753)