Land at Cartmel was granted to the monks of Lindisfarne in the 7th century by the King of Northumbria, but it was some 500 years later when William Marshall (1st Earl of Pembroke) founded the priory. Colonised by 13 monks from Bradenstoke Priory in Wiltshire, this Augustinian house was established c1190 and building commenced almost immediately.
Cartmel Priory was completed by 1233 but, because of its vulnerable position, it suffered damage on more than one occasion at the hands of Scottish raiders. In the first half of the 14th century a sturdy gatehouse was erected along the perimeter wall of Cartmel Priory as a defence against the continuing Border wars. At about the same time the southern end of the domestic buildings collapsed, but this happened as a result of natural causes and not through the wilful damage of invaders. Subsequently, the buildings were replaced on the northern side of the church. Possibly while this work was being carried out, the monks decided to install a Jesse window at the east end of the Town Choir. It was in this part of the church that the parishioners were allowed to worship.
During the 15th century a fair amount of work was carried out on Cartmel Priory church that has left it as a splendid example of changing ecclesiastical architecture. The earlier lancet windows at the East End were replaced with one huge, stained glass window, the beautifully carved oak misericords were installed in the choir, and the crossing tower was extended with an unusual lantern tower. This short, battlemented tower sits diagonally atop the existing crossing tower, a feature believed to be unique in England.
In 1536 Cartmel Priory came under the Act of Suppression, but the monks were reluctant to give up their life and their home without a fight. The following year most of them were hanged at Lancaster for treason, the priory was stripped of saleable assets, and the monastic buildings were largely demolished. As Cartmel Priory church already contained an area granted for use as the parish church, it was spared, and in the early years of the 17th century it was restored by Mr George Preston of Holker Hall.
Still in use today, the Priory Church of St Mary and St Michael saw a further period of major restoration during the 19th century, with essential repairs and a Victorian facelift, and further cosmetic additions were made in the 20th century. On the north side of the chancel is the Piper Choir, the oldest part of the church which retains its original stone-vaulted roof.
The gatehouse survives to a considerable extent as, at the time of Dissolution, it was being used as the courthouse of the manor. From 1624, the tower in the gatehouse was converted and used as a school until 1790, after which time it was sold on. By 1920 it had been purchased by a former churchwarden of Cartmel, keen to preserve the building as an important part of the town's heritage. With much repair and restoration the gatehouse now forms part of a Heritage Centre, allowing visitors gain an understanding of the area's history.