The 1240 Perambulation of the Forest of Dartmoor

The 1240 perambulation was ordered by the Crown. A writ dated 13 June 1240 directed the Sheriff of Devon and twelve knights of the county to walk the bounds of the Forest of Dartmoor and record them exactly. It was prompted by a dispute with four knights who owned land next to the forest, and the Crown was concerned about encroachment on the royal hunting ground. The walk itself is dated to 24 July 1240.

The original document is lost, but several near-contemporary copies survive, differing only in spelling. One account lists further perambulations in 1301, 1377, 1557, 1601, 1609 and 1786. The full circuit is roughly 50 miles.

Samuel Rowe's A Perambulation of the Antient and Royal Forest of Dartmoor prints the writ of 13 June 1240 in its Historical Documents (document V), directing the Sheriff of Devon to summon a jury of twelve knights to determine the forest's boundaries by perambulation, followed by the text of the perambulation itself (document VI, 24 Henry III, 1240). Rowe calls it the earliest perambulation of which there is any record. You can read the 1896 third edition free on the Internet Archive.