Henry of Grosmont, the Duke of Lancaster, inherited the castle from his father in 1345 and remodelled the great hall with a grander interior and roof.[83] On his death Blanche of Lancaster inherited the castle. Blanche married John of Gaunt, the third son of Edward III; their union, and combined resources, made John the second richest man in England next to the king himself.[2] After Blanche's death, John married Constance, who had a claim to the kingdom of Castile, and John styled himself the king of Castile and León.[71] Kenilworth was one of the most important of his thirty or more castles in England.[71] John began building at Kenilworth between 1373 and 1380 in a style designed to reinforce his royal claims in Iberia.[84] John constructed a grander great hall, the Strong Tower, Saintlowe Tower, the state apartments and the new kitchen complex. He made these renovations before his nephew took over his position.[85] When not campaigning abroad, John spent much of his time at Kenilworth and Leicester, and used Kenilworth even more after 1395 when his health began to decline.[86] In his final years, John made extensive repairs to the whole of the castle complex.[87]