Issue of Edward III of England – 3 February 1399), 1st Duke of Lancaster, fourth son. From the marriage of John of Gaunt and Blanche of Lancaster, daughter and heiress of the Duke of Lancaster, descended legitimate male heirs, the Lancasters (King Henry IV (1399-1413), who as Henry of Bolingbroke in 1399 deposed his first cousin King Richard II (1377-1399), and was followed by his son King Henry V(1413-1422) and the latter's son King Henry VI (1422-1471). This line ended in 1471 when King Henry VI's son Edward of Westminster, Prince of Wales was killed at the Battle of Tewkesbury and when he himself was deposed
Cham–Vietnamese War (1471) and once their economies recovered, these two kingdoms went to war again. When fighting resumed in 1471, the Champa kingdom found itself weakened and isolated. It has experienced numerous civil wars and, at one point, had five different rulers. For its earlier attack on Angkor, the Khmers ignored the Cham's request for assistance when Vietnam invaded. The Cham also requested Ming China to intervene by helping bring the Vietnamese back in line by force and demarcate the border between Champa and Vietnam. China, however, only verbally rebuked the Vietnamese for its incursion, which the Vietnamese ignored, proceeding with its attack