Swæfheard's charter [1] dated 1 March 689, in the second year of his reign, identifies his father as
Sæbbi, King of Essex (ac consensu patris mei Sebbe regis). He witnessed two charters of
Oswine,[2][3] one of which is dated 27 January 690.
Swæfheard apparently ruled West Kent as a sub king under his father,[4] while Oswine ruled the eastern half. According to Bede, Swæfheard was still reigning jointly with Withred in July 692.