A researcher at the University of East Anglia has uncovered previously overlooked excerpts from a lost letter by Pope Alexander II that could offer a new explanation for the events leading up to the Battle of Hastings in 1066. Professor Tom Licence found the letter in the Vatican archives while researching the Norman Conquest, and argues it shows the pope may have backed William the Conqueror's invasion of England because the English had aligned with his rival, the antipope Honorius II. The discovery matters because the battle, which decided whether Harold II or William of Normandy would hold the English throne, has traditionally been seen as a straightforward succession dispute rather than part of a wider papal power struggle.

In the letter, Alexander describes England as being led astray by an "evil head" and uses language branding the English as "followers of Satan," phrases Licence says only make sense once read against the context of the rivalry between Alexander and Honorius, whose position had weakened in 1064 but who still looked capable of a comeback in 1065. Licence, who specialises in both the Norman Conquest and ecclesiastical history, says most historians working on 1066 have not closely examined papal politics of the period, which is why the connection had previously gone unnoticed. He believes England had at least withdrawn support from Alexander, if not openly backed Honorius, giving the pope an added motive of "regime change" in England. The findings are detailed in Licence's new book, "Harold: Warrior King."