Ruins of St Mary's Abbey Church
The original abbey on the site was founded in 1055 and dedicated to Saint Olaf II of Norway. It was refounded in 1088 for Abbot Stephen and a group of monks from Whitby by the Anglo-Breton magnate Alan Rufus, who laid the foundation stone of the Norman church that year. The monks moved to York from a site at Lastingham in Ryedale in the 1080s and are recorded there in Domesday. Following a dispute and riot in 1132, a party of reform-minded monks left to establish the Cistercian monastery of Fountains Abbey. The surviving ruins date from a rebuilding programme begun in 1271 and finished by 1294.
The abbey's walled precincts were extended in the 12th century, so that by 1266 it was enclosed within a wall nearly three-quarters of a mile long. In 1318 the abbot received royal permission to raise the height of the wall and crenelate it; a stretch of this wall still runs along Bootham and Marygate to the River Ouse.
Ruins of the abbey church from the southern end The abbey church is aligned northeast-southwest, due to restrictions of the site. The Norman church had an apsidal liturgical east end, and its side aisles also ended in apses, though they were square on the exterior. Rebuilding began in 1270, under the direction of abbot Simon de Warwick, and was swiftly completed during a single campaign, such was the financial strength of the abbey. This completed the abbey church whose ruins are a prominent feature in York's Museum Gardens.