High Quality Content by WIKIPEDIA articles! Humphrey of Lancaster, 1st Duke of Gloucester, 1st Earl of Pembroke, KG (3 October 1390 – 23 February 1447), also known as Humphrey Plantagenet, was "son, brother and uncle of kings", being the fourth and youngest son of King Henry IV of England by his first wife, Mary de Bohun, brother to King Henry V of England, and uncle to the latter`s son, king Henry VI of England.