There has been a church on the site for over 1300 years since Etheldreda, Queen of Northumbria made a grant of lands to Wilfrid, Bishop of York c.674. Of Wilfrid's Benedictine abbey, which was constructed almost entirely of material salvaged from nearby Roman ruins, the Saxon crypt still remains; as does a frith stool, a 7th/8th century cathedra or throne. For a little while around that time it was the seat of a bishopric.
In the year 875 Halfdene (Halfdan Ragnarsson) the Dane ravaged the whole of Tyneside and Hexham Church was plundered and burnt to the ground.
About 1050 one Eilaf was put in charge of Hexham, although as treasurer of Durham, he probably never came there. Eilaf was instructed to rebuild Hexham Church which then lay in utter ruin. His son Eilaf II completed the work, probably building in the Norman style.
In Norman times Wilfrid's abbey was replaced by an Augustinian priory. The current church largely dates from that period (c.1170–1250), in the Early English style of architecture. The choir, north and south transepts and the cloisters, where canons studied and meditated, date from this period.
The east end was rebuilt in 1860. The Abbey was largely rebuilt during the incumbency of Canon Edwin Sidney Savage who came to Hexham in 1898 and remained until 1919. This mammoth project involved re-building the nave, whose walls incorporate some of the earlier church and the restoration of the choir. The nave was re-consecrated on 8 August 1908.
In 1996 an additional chapel was created at the east end of the north choir aisle. Named St Wilfrid's Chapel, it offers a place for prayer or quiet reflection.
Description harvested from Wikipedia - Hexham Abbey which has lots more information on the Abbey.
Due to a lack of time I did'nt have time to go inside to see if I could take photos in the Abbey. Maybe next time. There is a link to a website featuring internal photos at the bottom of this post.