1902: Who’s your uncle? If your name’s Arthur Balfour, Bob’s your uncle. During the late 1880s and 1890s, Robert Gascoyne-Cecil, 3rd marquess of Salisbury, used his position as prime minister to appoint his nephew to a series of important government posts. And when Salisbury resigned as prime minister in 1902, Balfour stepped effortlessly into his shoes.
Source: Andrew Roberts, Salisbury: Victorian Titan (1999), p. 827