The Stuart monarchs from James I onwards quarreled frequently with Parliament, resulting in civil war. The only English king ever tried and executed was Charles I, a Stuart. This led to a republic led by Oliver Cromwell, which proved unsuccessful. The dead king's son Charles II was invited to return as monarch, but constitutional issues around Parliament's powers continued under James II, leading to the Glorious Revolution of 1688 and William and Mary becoming joint monarchs on the condition they accept Parliamentary supremacy.