The Committee of Both Kingdoms,, was a committee set up during the Wars of the Three Kingdoms by the Parliamentarian faction in association with representatives from the Scottish Covenanters, after they made an alliance in late 1643.

The Solemn League and Covenant was an agreement between the Scottish Covenanters and the leaders of the English Parliamentarians in 1643 during the First English Civil War, a theatre of conflict in the Wars of the Three Kingdoms. On 17 August 1643, the Church of Scotland accepted it and on 25 September 1643 so did the English Parliament and the Westminster Assembly.