Kildare, James Fitzgerald, 20th earl of (kĭldârˈ) [key], 1722–73, Irish nobleman. He sat in the Irish House of Commons from 1741 until 1744, when he succeeded as earl of Kildare. He was created Viscount Leinster (in the English peerage) in 1747 and duke of Leinster in 1766. He emerged as a popular hero when he successfully opposed attempts to divert surplus Irish revenues to the British crown. He became lord deputy of Ireland in 1756.