It was founded as a priory in 1139 by William le Gros, the Earl of Yorkshire, and raised to the status of abbey in 1148 by Pope Eugene III. It was a house for Augustinian or black canons, who lived a communal life under the Rule of St Augustine but also undertook pastoral duties outside of the Abbey. Officers within the abbey included a cellarer, bursar, chamberlain, sacrist, kitchener and an infirmer. A medieval hospital also operated near the abbey, founded no later than 1322.