On 22 March 1639 he is recorded, with other Lords, as commanding 1,000 musketeers from Dalkeith to Edinburgh.

William Thomsone was ordered to pay Lord Sinclair 20,000 merks on 21 June 1644.

A letter written by Lord Sinclair on behalf of the Royalist James Graham, 1st Marquess of Montrose from Amsterdam was read out in Parliament on 30 May 1650.

[1][2] He was taken prisoner at the Battle of Worcester in September 1651 and was imprisoned in Windsor Castle, where he remained until March 1660, when he was liberated by General Monk.

She received from him a charter for the lands and barony of Ravenscraig and she was buried at the High Kirk of Glasgow.