six years earlier were restored to him. In England, Simon de Montfort (the Younger) defeated the king's supporters at the Battle of Lewes in 1264, capturing the king and the Lord Edward. Llywelyn began negotiations with de Montfort, and in 1265, offered him 30,000 marks in exchange for a permanent peace, in which Llywelyn's right to rule Wales would be acknowledged. The Treaty of Pipton, 22 June 1265, established an alliance between Llywelyn and de Montfort, but the very favourable terms given to Llywelyn in this treaty were an indication of de Montfort's weakening position. De Montfort was to die at the Battle of Evesham in 1265, a battle in which Llywelyn took no part. Supremacy in Wales After Simon de Montfort's death, Llywelyn launched a campaign in order to rapidly gain a bargaining position before King Henry had fully recovered. In 1265, Llywelyn captured Hawarden Castle and routed the combined armies of Hamo Lestrange and Maurice fitz Gerald in north Wales. Llywelyn then moved on to Brycheiniog, and in 1266, he routed Roger Mortimer's army. With these victories and the backing of the papal legate, Ottobuono, Llywelyn opened negotiations with the king, and was eventually recognised as Prince of Wales by King Henry in the Treaty of Montgomery in 1267. In return for the title, the retention of the lands he had conquered and the homage of almost all the native rulers of Wales, he was to pay a tribute of 25,000 marks in yearly installments of 3,000 marks, and could if he wished, purchase the homage of the one outstanding native prince - Maredudd ap Rhys of Deheubarth - for another 5,000 marks. However, Llywelyn's territorial ambitions gradually made him unpopular with some minor Welsh leaders, particularly the princes of south Wales. The Treaty of Montgomery marked the high point of Llywelyn's power. Problems began arising soon afterwards, initially a dispute with Gilbert de Clare concerning the allegiance of a Welsh nobleman holding lands in Glamorgan. Gilbert built Caerphilly Castle in response to this. King Henry sent a bishop to take possession of the castle while the dispute was resolved but when Gilbert regained the castle by trickery, the king was unable to do anything about it. Following the death of King Henry in late 1272, with the new King Edward I of England away from the kingdom, the rule fell to three men. One of them, Roger