, Lord Deputy of Ireland Elizabeth Cromwell Mary Cromwell Frances Cromwell Alma mater Sidney Sussex College, Cambridge Occupation Farmer; Parliamentarian ; Military commander Religion Puritan ( Independent ) Signature Military service Nickname(s) Old Ironsides Allegiance Roundhead Service/branch Eastern Association (1643–1645) ; New Model Army (1645–1646) Years of service 1643–51 Rank Colonel (1643 –