As a loyal supporter of Henry VI, Ros was attainted in Parliament on 4 November 1461. He led a section of the Lancastrian army which attacked John Neville's army at the Battle of Hedgeley Moor on 25 April, where his men fled, and then took part in the Battle of Hexham on 15 May 1464. The Lancastrian army was crushed by Neville; Ros was subsequently found hiding with lord Hungerford in a wood. He was beheaded the next day at Newcastle for treason, and the Ros lands were confiscated. Belvoir Castle was given to William, Lord Hastings.