a Romani castle in Britannia Inferior, whose site is unknown.
It is mentioned in the Notitia Imperii
as the quarters of a troop of Numidian horse (Mauri Aureliani) in the 3rd century A.D. Antiquaries refer it to Appleby
on the Eden, and its name, containing the Celtic word Avon,
water, indicates its position near a stream. Watchcross
in Cumberland also claims to be the ancient Aballaba.
It was certainly, however, one of the forts upon the rampart erected by Hadrian in A.D. 120, between the rivers Esk and Tyne, to protect the province of Britain from the incursions of the Caledonians.