Thomas Harrison rose from trooper at the Battle of Powick Bridge in 1642 to commanding officer of Parliament's forces within a decade, and he signed Charles I's death warrant in 1649 without apparent hesitation. What sets him apart from most regicides is what came after: Harrison treated the king's execution not as an endpoint but as a hinge, the opening act of a prophesied Fifth Monarchy in which Christ himself would reign on earth and the saints would govern in his name.
That conviction, shared by an organized movement of radical Puritans reading the Book of Daniel as a countdown, put Harrison on a collision course with the man he had helped bring to power. When Cromwell dissolved the Fifth Monarchist-favored Barebone's Parliament and took the title of Lord Protector in 1653, Harrison read it as a betrayal of the cause both men had fought for, and said so. He was arrested and imprisoned four times before the Restoration reached him, a general punished by his own side for refusing to trade prophecy for pragmatism.
An episode of the podcast The World Turned Upside Down lays this out with the care of the academic historians who edit the series, tracing Harrison's military record alongside his theology rather than treating the Fifth Monarchist label as a footnote. It does not soften what followed: Harrison was the first regicide executed after the 1660 Restoration, hanged, drawn and quartered while a movement that had briefly held real political power watched its most visible general become its most visible martyr.
Recording Harrison's story here recovers what a doctrinal account of the Fifth Monarchists alone would miss: an apocalyptic timetable its adherents were willing to resist Cromwell over, and die for.