Who was King of England, Scotland, and Ireland during the First English Civil War?

Charles I (19 November 1600 – 30 January 1649) was King of England, Scotland, and Ireland from 27 March 1625 until his execution in 1649. He was born into the House of Stuart as the second son of King James VI of Scotland, but after his father inherited the English throne in 1603 (as James I), he moved to England, where he spent much of the rest of his life. He became heir apparent to the three kingdoms of England, Scotland, and Ireland in 1612 on the death of his elder brother Henry Frederick, Prince of Wales.

After his succession in 1625, Charles quarrelled with the Parliament of England, which sought to curb his royal prerogative. Charles believed in the divine right of kings, and was determined to govern according to his own conscience.

From 1642, Charles fought the armies of the English and Scottish parliaments in the First English Civil War. After his defeat in 1645, he surrendered to a Scottish force that eventually handed him over to the English Parliament (the "Long Parliament"). Charles refused to accept his captors' demands for a constitutional monarchy, and temporarily escaped captivity in November 1647. Re-imprisoned on the Isle of Wight, Charles forged an alliance with Scotland, but by the end of 1648 the Parliamentarian New Model Army had consolidated its control over England. Charles was tried, convicted, and executed for high treason in January 1649.