Robert Devereux, 2nd Earl of Essex (10 November 1566 – 25 February 1601), a favourite of Queen Elizabeth I of England, is the best-known of the many holders of the title "Earl of Essex." He was a military hero and royal favourite, but following a poor campaign against Irish rebels during the Nine Years War in 1599, he began a pattern of defying the Queen. In 1601, he gathered supporters and marched to London in a failed attempt to gain an audience with Elizabeth. He was subsequently executed for treason.