Prior to the 1066 Norman conquest, the castle was held by Sir John de Mitford, whose only daughter and heiress, Sybilla Mitford, was given in marriage by William the Conqueror to the Norman knight, Richard Bertram. In the late 11th century, it was an earthwork fortress of the Bertram family, and of record as William Bertram's oppidum in 1138. In 1215, it was seized by John de Balliol, King of Scotland's troops., which was clever of him as he didn't become king until 1292. In 1264, the castle was held by the third Roger Bertram, but in that year, it was seized from him and committed to the custody of William de Valence, 1st Earl of Pembroke, King Henry's half-brother. It was held by Alexander de Balliol, the son of John de Balliol and the elder brother of King John, in 1275. During the rebellion in Northumberland set in the 1310s, Mitford Castle was seized from the Valence family by Sir Gilbert de Middleton. In 1315, Mitford Castle was used by Sir Gilbert for kidnappings and as a prisoner hold, when Ralph de Greystock seized de Middleton for treason. There are conflicting accounts over the castle's destruction. One theory is of a fire during Middleton's rebellion. Another theory is that it was destroyed by the Scots in May 1318 during Middleton's imprisonment in the Tower of London. It was certainly destroyed by 1323 as records of an inquest held that year after the death of Sir Aymer de Valence state Mitford Castle to be " entirely destroyed and burnt." At the time of his death in 1335, Mitford Castle had been seized from its then holder, David de Strathbogie, 12th Earl of Athol, 2nd baron. The estate, including the castle, was purchased by the Bruce Shepherd family in 1993 from the Mitford family. English Heritage grants in the 2000s were offered towards repairs, restoration and preservation, and some of the work has been completed.
Architecture
The castle ruins are ashlar quality squared stone construction. The inner ward was built in the early 12th century. The western section of the inner ward is on a stepped plinth and includes a large rounded archway. The eastern section of the inner ward wall has a rounded round arch to the outer ward of 19th-century reconstruction. The inner ward contains an unusual pentagonal keep that stands to the first floor and dates from the early 13th century. The keep was built on the highest point at the northern most area of the castle with each of its five sides being of a different dimension, and its internal area measuring approximately. The triangular outer ward to the south and east was built in the late 12th century. The divided basement contains two barrel-vaulted chambers that may have been used as cisterns. The chapel, built in the mid 12th century and largely destroyed in the early 19th century, is also of squared stone. A sanctuary or chancel arch remain. A cemetery was uncovered in 1939 north of the chapel with headstones dating to the 12th century. At least one stone was moved to the Mitford churchyard with others removed or vandalised. Remains of a 12–13th century east curtain wall of squared stone include a gateway to a barmkin, mural chambers, garderobe, and a round arch. This east curtain wall area is flanked by a semicircular breastwork; the strongest part of the building. The west curtain wall and structures are also of the 12–13th century and squared stone, with different builds and masonry types found across three different sections. An inner courtyard used as a garden and orchard measured approximately by.
