Columba and his nephew Drostan founded a monastery here in the 6th century, of which no trace remains. The Book of Deer is a most interesting relic of the monks, which was discovered in 1857 in the Cambridge University library by Henry Bradshaw. It was probably stolen during the Wars of Scottish Independence by English troops. It is a small manuscript of the Gospels in the Vulgate, fragments of the liturgy of the Celtic church, and notes, in the Gaelic script of the 12th century, referring to the charters of the ancient monastery, including a summary of that granted by David I of Scotland. These are among the oldest examples of Scottish Gaelic. The manuscript is also adorned with Gaelic designs. It had belonged to the monks of Deer and been in the possession of the University Library since 1715. It was edited by John Stuart for the Spalding Club, by whom it was published in 1869 under the title The Book of Deer (Leabhar Dhèir in Gaelic).
In 1218 William Comyn, earl of Buchan, founded the Abbey of St Mary of Deer, now in ruins, 3⁄4 mi (1.2 km) farther up the river than the monastery and on the opposite bank. Although it was erected for Cistercians from the priory of Kinloss, near Forres, the property of the Columban monastery was removed to it. The founder (died 1233) and he and his countess were buried in the church. The parish is rich in antiquities, but the most noted of them is the Stone of Deer, a sculptured block of syenite, which stood near the abbey; it was destroyed in 1854.