Henry was born in the tower above the gatehouse of Monmouth Castle in Wales, and for that reason was sometimes called Henry of Monmouth. He was the son of Henry of Bolingbroke (later Henry IV of England) and Mary de Bohun. His father's cousin was the reigning English monarch, King Richard II. Henry's paternal grandfather was the influential John of Gaunt, a son of King Edward III. As he was not close to the line of succession to the throne, Henry's date of birth was not officially documented, and for many years it was disputed whether he was born in 1386 or 1387. However, records indicate that his younger brother Thomas was born in the autumn of 1387 and that his parents were at Monmouth in 1386 but not in 1387. It is now accepted that he was born on 16 September 1386.