Tavistock Abbey, also known as the Abbey of Saint Mary and Saint Rumon, is a ruined Benedictine abbey in Tavistock, Devon.
It was thought the the abbey was founded in 961 by Ordgar, Ealdorman of Devon, but is now thought that it was founded by his son Ordwulf in 974. In 981 the charter of confirmation was granted by King Æthelred the Unready, Ordwulf's nephew. It was endowed with lands in Devon, Dorset and Cornwall, and became one of the richest abbeys in the west of England.
St Rumon was probably a brother of St Tudwal of Tréguier, but little else is known of him beyond that he was probably an Irish missionary and many churches in Devon and Cornwall in England were named after him. Some authorities have identified him with St Ronan (1 June) who is venerated in Brittany, but others believe that he and St Kea were British monks who founded a monastery at Street, Somerset.
The abbey church, was destroyed by Danish raiders in 997, but then rebuilt under Lyfing, the second abbot. Abbot Lyfing as well as his successor Abbot Ealdred, both became Bishops of Worcester. It is thought that Abbot Ealdred crowned King William the Conqueror. The church was further rebuilt in 1285 and the greater part of the abbey between 1457 and 1458.
The abbey had considerable land holdings in Cornwall and three churches there are dedicated to St Rumon: Ruan Lanihorne, Ruan Major and Ruan Minor. In the Domesday Book, the abbey held the manors of Sheviock, Antony, Rame, Tregrenna, Penharget and Tolcarne, while four other manors formerly theirs had been taken by Robert of Mortain. Only Sheviock was in the hands of the abbey while Ermenhald held five manors from it. These lands in the extreme south-east of Cornwall were the reason for that district being part of Devon from the medieval period until 1844.
In early times the Isles of Scilly were in the possession of a confederacy of hermits. King Henry I gave the hermits' territory to the abbey of Tavistock, which established a priory on Tresco that was abolished at the Reformation.
On 3 March 1539 the last abbot, John Peryn, together with twenty monks, surrendered the abbey to the king and was granted a pension of a hundred pounds. The abbey was the second wealthiest in Devon at the time of the Dissolution of the Monasteries 1536–1541. In 1540 the Abbey and its lands were granted by King Henry VIII to John Russell, 1st Baron Russell of Chenies in Buckinghamshire .The Russell family long maintained a close connection with Tavistock, and in 1694 the family received the additional titles of Marquess of Tavistock and Duke of Bedford.
Before 1810, the family had only one formal residence in Devonshire, namely the townhouse of Bedford House in the City of Exeter. In 1810, John Russell, 6th Duke of Bedford built a new residence to the designs of Sir Jeffry Wyattville named Endsleigh Cottage at Milton Abbot, near Tavistock, a former manor belonging to the Abbey. It was a large cottage orné used as a summer holiday home, still standing but sold in the 20th century by the Russell family.
Nothing remains of the abbey today, except the refectory, two gateways and a porch.