Charles I faced growing distrust from Parliament due to religious differences. He needed money from Parliament to fund wars but took unpopular actions like forced loans, imprisonment without cause, and quartering of soldiers. This led to conflicts, including with Scotland over a new Anglican prayer book. It resulted in an English Civil War between Royalists and Parliamentarians led by Oliver Cromwell, who defeated Charles I. The Rump Parliament then condemned Charles to death for treason, declaring England a Commonwealth under Cromwell's rule.