He caused a succession crisis by promising the throne to several heirs

Although Edward had no power to make any promises because the English monarchy was not hereditary, it appears that he did so anyway, which led to a succession issue after his death. He most likely saw Harold Godwinson as his successor, and the two men worked out a deal for Harold to succeed Edward as king. He was killed at the Battle of Hastings in the same year, though, so he didn't live long (1066). Harold was the child of Earl Godwin of Wessex, who had essentially seized power even while Edward was still alive.

According to a medieval legend, Edward had made the decision to remain celibate before getting married and, given his support for the Normans, would have always wanted William the Conqueror to replace him. It is said that during a time when Godwin was banished after having a disagreement with Edward, Edward would have offered William the succession. The Normans asserted that in order to ensure William's succession, Edward dispatched Harold Godwinson to Normandy in 1064. In the end, this paved the way for William the Conqueror to invade at the Battle of Hastings. Harold is thought to have received the throne from Edward the Confessor as he lay dying, but William later asserted that his pledge would take precedence.