In response to the growing unrest, on 4 January Charles made an unsuccessful attempt to arrest the Five Members, one of whom was Pym. Having failed to do so, he left London accompanied by many Royalist MPs and his supporters in the Lords, a major tactical mistake as it gave the opposition majorities in both houses. When the First English Civil War began in August, Pym headed the Committee of Safety; his reputation for integrity and ability to keep a diverse coalition of interests together was crucial to surviving the first 18 months of the conflict.