Osthryth was murdered in 697, for reasons unknown; according to Bede the murderers were "her own people, the Mercian chieftains". Bede records that Peada's death, forty years earlier, stemmed from "the treachery, it is said, of his own wife"; Peada's wife was Ealhflæd, Osthryth's sister. Hence Osthryth's murder may have been in revenge for Peada's assassination, though it has also been interpreted more directly as a sign of continuing hostility between Northumbria and Mercia. Osthryth was buried at Bardney in Lindsey, the monastery where, at her urging, the relics of her uncle, Oswald of Northumbria, were kept and revered, though evidence of resistance at Bardney to the cult of Oswald is also indicative of the poor relations between the two kingdoms.