The Battle of Maserfield was assumed for much of the twentieth century to have taken place at what is now
Oswestry in
Shropshire. The
etymology of this name is "Oswald's Tree", while the traditional Welsh name for the same place is
Croesoswald ("Oswald's Cross"); although an association with King Oswald of Northumbria is not certain, the name is popularly assumed to refer to him. In the mid -seventh century, Oswestry is thought to have probably still been in the territory of
Powys. If this location is correct, it would mean Oswald was in the territory of his enemies, which would suggest he was on the offensive. However, neither the Welsh nor English names for the battle site have been securely identified with modern reflexes or localised, and site of the battle is still debated among scholars; in 2020,
Andrew Breeze suggested
Forden in Powys, particularly on the basis of place-names that seem to be associated with the battle in the Welsh
Canu Heledd. The site of the battle is named
Maserfelth (with the variant spelling
Maserfeld) in the principal source for the battle, Bede's
Historia ecclesiastica gentis Anglorum. The second element of this name is the
Old English word that became
field in present-day English. The first element is debated: it has been taken as a possibly unique Old English attestation of the word
mazer; a word having something to do with Welsh
maes ('field'); or to be the Welsh female name
Meiser (an argument supported by the place-name
Dyffryn Meiser in
Canu Heledd). The
Annales Cambriae record a battle for 644 at a site which they call by the
Old Welsh name
Cocboy; the same name is found in a later form as
Cogwy in
Canu Heledd; and the battle described in these Welsh texts is agreed to be identical with the Battle of Maserfield known from Bede (albeit that
Canu Heledd's account may owe little to historical reality). Andrew Breeze has etymologised this name as a
compound of the
Brittonic word *
kok- ('rock') and a personal name *
Boia, thus meaning 'hill of Boia'. ==Outbreak of war==