I (vaguely) recall learning about the Roundheads and the Cavaliers at school.
Is somewhat relevant here considering the wars of the three kingdoms kicked off with a dispute about whether the divinely mandated monarch (both sides agreed on that) was in charge of both state and church or just the former. Charles thought both and a lot of people in the Church of Scotland thought just the former.
That gave us the Scottish Bishops war and after the English parliament went “not really interested in funding that thanks” some rather ill advised moves in Ireland by Charles triggered the 1641 rebellion there. Giving us two of the kingdoms in the wars of the three kingdoms.
Then finally the English civil war started due to the political disagreements in England around the repercussions of Charles losing the Bishop wars and how to deal with the Irish rebellion.