Who is Lord St. Vincent from Lord Hornblower and what is their importance?

Lord St. Vincent appears in the opening of the novel, when he attends church with Hornblower and other naval dignitaries. Dressed in resplendent clothing, he cuts an impressive figure regardless of his age and gout. St. Vincent interrupts the church service when he receives the news about the mutiny of Flame, and he specifically seeks out Hornblower to quell the mutiny. Lord St. Vincent gives Hornblower a wide degree of personal latitude in dealing with the mutiny. It is interesting to note that Lord St. Vincent is a lightly fictionalized version of the historic Lord St. Vincent, so-named due to a great naval victory under his command.