Before the Civil War, Belasyse and his family had a long running confrontation with Sir Thomas Wentworth, a close advisor to King Charles I, primarily over local government issues in Yorkshire.
[2] He had Roman Catholic leanings, and married into a known recusant family, but stayed within the laws of the time and attended Anglican Church services.
During the summer of 1642, in the months before the war started while Charles resided in York, Fauconberg and his sons Henry and John were prominent supporters.
[3][4] Fauconberg supported William Cavendish, Marquis of Newcastle, followed the fortunes of that nobleman in the siege of York, which held out three months against powerful Scottish and Parliamentary armies.
When the Royalists garrison of York and a relieving army under the command of Prince Rupert lost the Battle of Marston Moor on 2 July 1644, Newcastle and Fauconberg escaped into exile, embarking at Scarborough, for Hamburg.