 Following King John's death, Llywelyn concluded the Treaty of Worcester with his successor, Henry III, in 1218.During the next fifteen years, Llywelyn was frequently involved in fights with Marcher lords and sometimes with the king, but also made alliances with several major powers in the Marches.The Peace of Middle in 1234 marked the end of Llywelyn's military career, as the agreed truce of two years was extended year by year for the remainder of his reign.