Roy Maurice Keane (born 10 August 1971) is an Irish football manager and former professional football player. He is the assistant manager of the Republic of Ireland national football team and Aston Villa. In his 18 year long playing career, he played for Cobh Ramblers, Nottingham Forest, and Manchester United, before ending his career at Celtic. Keane was a dominating defensive midfielder, noted for his aggressive and highly competitive style of play, an attitude that helped him excel as captain of Manchester United from 1997 until his departure in 2005. Joining the club in 1993, Keane helped United achieve a sustained period of success during his twelve year tenure at the club. He then signed for Celtic but retired as a player less than a year later. Keane is regarded by many football players, managers and critics as the greatest captain in English football history.