Complex sentence: Warwick died himself at the Battle of Barnet in 1471, but after being briefly held by Richard Hyet, Henry VII restored St Briavels Castle to Neville's widow, Anne Neville, 16th Countess of Warwick.
Split into simpler sentences: Warwick died himself at the Battle of Barnet in 1471. However, Henry VII later restored St Briavels Castle to Neville's widow, Anne Neville, 16th Countess of Warwick.