The abbey is thought to have been founded in 675 either by Cissa, viceroy of Centwine, king of the West Saxons, or by his nephew Hean, in honour of the Virgin Mary, for twelve Benedictine monks.
Endowed by successive West Saxon kings, it grew in importance and wealth until its destruction by the Danes in the reign of King Alfred, and the sequestration of its estates by Alfred because the monks had not made him a sufficient requital for vanquishing their enemies.
By the 950s the abbey was in a decayed state, but in about 954 King Eadred appointed Æthelwold, later Bishop of Winchester, abbot.
[5][c][d] The Chronicle of the Monastery of Abingdon (Historia Ecclesie Abbendonensis) was written at the abbey in the twelfth century.
Abbots after the Norman Conquest included Faritius, physician to Henry I of England (1100–17), and Richard of Hendred, for whose appointment the King's consent was obtained in 1262.
With the rest of his community he signed the surrender of his monastery in 1538, receiving the manor of Cumnor for life or until he had preferment to the extent of £223 per annum.
Apparent ruins in the Abbey Gardens are Trendell's Folly, built in the nineteenth century.