"The Book of Deer, illuminated manuscript written in Latin, probably in the 9th century, at a monastery founded by St. Columba at Deer Abbey (now in Aberdeenshire, Scotland) and containing 12th-century additions in Latin and an early form of Scottish Gaelic. The Book of Deer includes the whole of the New Testament Gospel of St. John and parts of the other three Gospels, an early version of the Apostles’ Creed, and a later charter granted to the monks by King David I of Scotland. The illuminations—capitals, borders, and pictures of the Evangelists—resemble those in earlier Irish Gospels. The version of the Gospels is that used in Ireland (combining the Vulgate with earlier readings): the manuscript is clearly a careless transcript of a corrupt text. It was discovered in 1860 in the library of the University of Cambridge.
The 12th-century Gaelic memorandums (the earliest extant Gaelic written in Scotland) provide information on a little-known period of Scottish history—the end of the Celtic period. They give details of clan organization, land divisions, and monastic land tenure and an account of the monastery’s foundation.”