September 29, 792. Æthelred of Northumbria marries Ælfflæd, daughter of Offa of Mercia (at Catterick)
This marriage, mentioned in the Chronicle and located at Catterick by Simeon of Durham, can be seen from Æthelred's point of view as part of his efforts to ensure his security on the throne. He was already killing potential rivals at home, and a marriage with the Mercian king's daughter would make raids from the south less likely (such as plagued Eadberht in 740, when he raided the Picts and Offa's predecessor Æthelbald raided Northumbria). It would also give him a strong ally to call on if he were threatened.