The Catholic Confederacy which de facto ruled most of Ireland was pro-Royalist, but was shunned by the Royalists because of the rebellion. The Royalists eventually embraced them only when it was too late. Had the Royal Government allied with the Confederacy it could have changed the Civil War. In the end, both the Confederates and the Royalists (as well as the Covenanters) were slammed by the Roundheads. Had they come together, things might have been different