Cadwallon ap Cadfan (died 634)A difference in the interpretation of Bede's dates has led to the question of whether Cadwallon was killed in 634 or the year earlier, 633.

Cadwallon Lawhir ap Einion (c. 460 – c. 534), usually known as Cadwallon Lawhir ("Long Hand") and also called Cadwallon I by some historians, was a king of Gwynedd around 500.