Previous king: Richard II (cousin) Reigned: 1399-1413 Next king: Henry V (son)Henry IV became king by rebelling against Richard II who had exiled him and taken his lands. Henry imprisoned Richard, who died in mysterious circumstances. Richard's heir should have been Edmund de Mortimer, who was a direct descendent of Edward III. Henry started a new dynasty called the House of Lancaster, as he was descended from John of Gaunt, Duke of Lancaster. At Henry's coronation, he made a speech in English. Before this, the official language of the court was French, ever since William I conquered England.