Cromwell was an Irish rock band formed in the early 70s in Drumcondra, Dublin, consisting of Mick O'Hagan (vocals), Patrick Brady (guitar), Michael Kiely (bass), and Derek Dawson (drums). After O'Hagan's departure, the band continued as a trio, with Brady and Kiely taking over on vocals. The band recorded and self-released a number of singles and one album between 1973 and 1975, when they broke up. Brady and Kiely went on to form a band called The Establishment.