Libellus de exordio

The Libellus de exordio atque procursu istius, hoc est Dunhelmensis, ecclesie (English: Tract on the Origins and Progress of this the Church of Durham), in short Libellus de exordio, is a historical work of marked literary character composed and compiled in the early 12th-century and traditionally attributed to Symeon of Durham. It relates the history of bishopric and church of Durham and its predecessors at Lindisfarne and Chester-le-Street (Cunecacestre). It is sometimes also known as the Historia Dunelmensis ecclesiae (English: History of the Church of Durham).

The text survives in a number of medieval manuscripts, each with its own history, and containing different interpolations and notes. An English translation was published in 1885.

Its coverage extends from the beginning of Christianity among the English of Northumbria and the foundation of a bishopric at Lindisfarne, to the death of Bishop William of Saint-Calais in 1096.