* It possibly arose as a version of the ligature, Œ, of the digraph"Oe ", with the horizontal line of the "e" written across the "o".
* It possibly arose in Anglo-Saxon England as an O and an I written in the same place: compare Bede's Northumbria in Anglo-Saxon period spelling ''Coinualch'' for standard ''Cēnwealh'' (a man's name) (in a text in Latin). Later the letter ø disappeared from Anglo-Saxon as the Anglo-Saxon sound /ø/ changed to /e/, but by then use of the letter ø had spread from England to Scandinavia
* It possibly arose in Anglo-Saxon England as an O and an I written in the same place: compare Bede's Northumbria in Anglo-Saxon period spelling ''Coinualch'' for standard ''Cēnwealh'' (a man's name) (in a text in Latin). Later the letter ø disappeared from Anglo-Saxon as the Anglo-Saxon sound /ø/ changed to /e/, but by then use of the letter ø had spread from England to Scandinavia
by Qorptocx November 2, 2018