The contemporary evidence for Edwin's life is very limited. At some point during the reign of his half-brother Ęthelstan, Edwin witnessed a charter, S 1417, at New Minster, Winchester, granting lands to one Alfred, a thegn (minister) of King Ęthelstan. Edwin witnesses the charter immediately after his half-brother and is described as ętheling (clito). The Anglo-Saxon Chronicle states that Edwin drowned at sea in 933. The Francian Annales Bertiniani compiled by Folcuin provide more detail:
For in the year of the Incarnate Word 933, when the same King Edwin, driven by some disturbance in his kingdom, embarked on a ship, wishing to cross to this side of the sea, a storm arose and the ship was wrecked and he was overwhelmed in the midst of the waves. And when his body was washed ashore, Count Adelolf, since he was his kinsman, received it with honour and bore it to the monastery of Saint Bertin [at Saint-Omer] for burial.
Later writers such as William of Malmesbury and Simeon of Durham rewrote Edwin's death. Sir Frank Stenton saw their reports as suggesting that "a rebellion against Athelstan may have been organised within the royal house itself". Simeon's version baldly states that "King Ęthelstan commanded that his brother Edwin be drowned at sea". William's account is much longer and associates Edwin's death with an earlier plot to blind Ęthelstan and replace him with Edwin. In this version, Ęthelstan is convinced by jealous courtiers to have Edwin sent to sea in a leaky boat, without oars, without food, and without water. Despairing, Edwin throws himself into the sea and drowns (wikipedia.com)