^Bede gives the year of Oswald's death as 642, however there is some question as to whether what Bede considered 642 is the same as what would now be considered 642. R. L. Poole (Studies in Chronology and History, 1934) put forward the theory that Bede's years began in September, and if this theory is followed (as it was, for instance, by Frank Stenton in his notable history Anglo-Saxon England, first published in 1943), then the date of the Battle of Heavenfield (and the beginning of Oswald's reign) is pushed back from 634 to 633. Thus, if Oswald subsequently reigned for eight years, he would have actually been killed in 641. Poole's theory has been contested, however, and arguments have been made that Bede began his year on 25 December or 1 January, in which case Bede's years would be accurate as he gives them.
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