Chef de brigade William Tate was the Irish-born American commander of a French invasion force known as La Légion Noire ("The Black Legion") which invaded Britain in 1797, resulting in the Battle of Fishguard.

In 1793, French Consul Michel Ange Bernard Mangourit wanted to capture Florida from Spain.

[3] In February 1794, Jean Antoine Joseph Fauchet, arrived in Philadelphia as the new French ambassador, and rescinded Tate's commission.

[4] South Carolina threatened to arrest Tate for treason, and he fled to France in 1795,[3] where he was given command of the Légion Noire during the 1797 invasion of Britain.

[5] Many historians, following E. H. Stuart Jones, the author of The Last Invasion of Britain (1950), have suggested that William Tate was about 70 years old in 1797; he was in fact 44.