The largely fictional stories of ancient Britain written by
Geoffrey of Monmouth use the names of many historical personages as characters, and the use of these names is a literary convenience made in order to advance the plot of Geoffrey's stories. One of these stories uses the names of Iago's son Cadfan and other contemporary people, telling of how a certain Edwin spent his exiled youth in Gwynedd, growing up alongside Iago's grandson, the future King Cadwallon. There is no historical basis for this story, as is readily acknowledged in the preface of works on the subject. Nevertheless, a "traditional" story arose blending Geoffrey's fiction with known history, implying that the future King
Edwin of Northumbria had actually spent his youth in Gwynedd, growing up alongside Iago's grandson, the future King Cadwallon. In point of fact, Cadwallon and Edwin were enemies with no known youthful connections: King Edwin invaded Gwynedd and drove King Cadwallon into exile, and it would be Cadwallon, in alliance with
Penda of Mercia, who would ultimately defeat and kill Edwin in 633 at the
Battle of Hatfield Chase (). The story that they had spent an idyllic youth together may have had a romantic appeal. What is known from history is that in 588 King
Ælla of Deira died, and
Æthelfrith of Bernicia took the opportunity to invade and conquer
Deira, driving Ælla 's 3-year old infant son, the future Edwin of Northumbria, into exile. Edwin would eventually ally himself with
Rædwald of East Anglia in 616, defeating and killing Æthelfrith and becoming one of
Northumbria's most successful kings. Edwin's life in exile is unknown, and there is no historical basis for placing him in Gwynedd. == See also ==