Nine of the characters in Sir Walter Scott's Rob Roy bear this name. There are
(1) the London merchant and Sir Hildebrand, the heads of two families;
(2) the son of the merchant is Francis, the pretendu of Diana Vernon;
(3) the “distinguished” offspring of the brother are Percival the sot, Thorncliffe the bully, John the game-keeper, Richard the horse-jockey, Wilfred the fool, and Rashleigh the scholar, by far the worst of all. This last worthy is slain by Rob Roy, and dies cursing his cousin Frank, whom he had injured in every way he could contrive.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894