sentences:  These Lancaster kings initially survived the treason of their Edmund of Langley (York) cousins but eventually were deposed by the merged Lionel/Edmund line in the person of Edward IV.Internecine killing among the Yorks left Richard III as king, supported and then betrayed by his cousin Buckingham, the descendant of Thomas of Woodstock.Finally, the Yorks were dislodged by the remaining Lancastrian candidate, Henry VII of the House of Tudor, another descendant of John of Gaunt, who married the eldest daughter of Yorkist King Edward IV.