Cadfan ap Iago (c. 569 – c. 625) was King of Gwynedd (reigned c. 616 – c. 625). Little is known of the history of Gwynedd from this period, and information about Cadfan and his reign is minimal. The historical person is known only from his appearance in royal genealogies, from his grant to Saint Beuno for the monastery at Clynnog Fawr, and from his inscribed gravestone in Llangadwaladr church. Cadfan was the son and successor of King Iago ap Beli, and is listed in the royal genealogies of the Harleian genealogies and in Jesus College MS. 20. Cadfan came to the throne near the time of the Battle of Chester () in 616, in which the Northumbrians under Æthelfrith decisively defeated the neighboring Welsh Kingdom of Powys and then massacred the monks of Bangor Is Coed. However, there is no evidence that Gwynedd had any part in the battle, so Cadfan's accession at that time appears to be no more than coincidence. Cadfan was succeeded as king by his son, Cadwallon ap Cadfan. Gravestone Cadfan's gravestone is at Llangadwaladr () on Anglesey, a short distance from the ancient llys () of the kings of Gwynedd, and reputed to be their royal burial ground. The inscription refers to him as sapientisimus (), and as this term is historically used for ecclesiastics, it suggests that at some point, Cadfan had resigned as king to live a consecrated life. Saint Beuno Saint Beuno and the monastery at Clynnog Fawr are often cited in conjunction with Cadfan. An 1828 article by P. B. Williams in the Cymmrodorion cited a manuscript stating that a local prince named 'Gwytheint' gave Clynnog Fawr to God and Saint Beuno, who was then Abbot at the monastery at Clynnog, and that the donation was free from taxes and obligations forever. It goes on to say that Beuno founded a convent at Clynnog in 616, and that Cadfan was Beuno's great patron, promising him extensive lands. The promise was carried out by Cadfan's son, King Cadwallon, and that Cadwallon was given a golden sceptre worth 60 cows as a token of acknowledgment. (Life of Saint Beino) (Rees was the editor of the 1828 Cymmrodorion that published P. B. Williams' account.) There are minor variations of these accounts, sometimes with the details rearranged, such as in Rice Rees' 1836 Essay on the Welsh Saints, where he says that Cadfan (rather