Question: how did llywelyn the great die?
Answer: Princess Joan died in 1237 at Garth Celyn and Llywelyn suffered a paralytic stroke later in the same year. He died at the Cistercian Abbey of Aberconwy, his own foundation, on 11th April, 1240 and was buried there. His stone coffin was later removed to the parish church of Llanwrst, where it can still be seen.