What did roundheads have to do with Charles the 1st?

The Roundheads were supporters of the Parliament during the English Civil War, opposing King Charles I, who believed in the divine right of kings and sought to maintain absolute power. The conflict between the Roundheads and the Royalists (Cavaliers) ultimately led to a civil war, resulting in Charles I's capture, trial, and execution in 1649. The Roundheads played a crucial role in challenging the monarchy and shaping the future of England's governance.