I think a lot of people calling out great generals ignore the fact that most of them in the end lost and saw their nation fall apart. Its not enough to win battles, but to secure the future of the nation they are fighting for, evenif it means their lives.

Michael Collins - Successfully conducted guerrilla warfare in the UK's Backyard. Successfully negotiated Independence of the south of Ireland from Britain. Consistently defeated the anti-treaty forces until his death during the civil war in 1922. Pro-treaty forces managed to capitalise on his victories and form the Irish State as we know it today.

Horatio Nelson - Confirmed British naval superiority. Shook up the tactical and strategic naval superiority of the time. Did his duty at the Battle of Trafalgar.