Henry IV was born in April 1367 and was the only son of John of Gaunt, the son of Edward III, and Blanche, the daughter of Henry Grismond, Duke of Lancaster. Known as Henry of Bolingbroke after his birthplace in Lincolnshire, he was made a knight of the Garter in 1377. In 1380, at the age of 13, he married Mary de Bohun, the youngest daughter and coheiress of Humphrey, the last Earl of Hereford. They had four sons and two daughters before her death at the age of 24, in 1394. As the Earl of Darby, Henry entered the House of Lords in 138 ....