Visitors to Malmesbury might be forgiven for not noticing that the town ever possessed a castle. We are not really sure exactly where it used to be (although it was probably in the area around the Old Bell) and the castle no longer exists. And yet reliable documentary sources confirm that the castle was once of national importance and that extraordinary events took place here during its brief life, 1118-1216. The castle was built in around 1120 by Roger, the bishop of Salisbury and the chief minister of King Henry I as part of a network of fortifications that he established across his diocese. It played a very prominent part in the civil war of the mid-12th century that is sometimes known as The Anarchy, when Stephen and his cousin, Matilda, fought for control of England. King Stephen took the castle from Bishop Roger in 1139 and placed a garrison in the castle loyal to him. His enemy, the Empress Matilda, and her general, Robert of Gloucester, tried repeatedly but unsuccessfully in the 1140s to take Malmesbury.
The castle mattered a lot to King Stephen, and during these years he visited Malmesbury many times to bolster the defence of the castle. For the Empress Matilda based in Devizes and Robert of Gloucester in Bristol, Malmesbury Castle in 1144 represented a major problem. It was close but it remained stubbornly loyal to their enemy, King Stephen. From this hostile base, the constable of Malmesbury, Walter of Pinkney, sent out raiding parties that ravaged their own lands. In 1144 the decision was taken to lance the boil and end Stephen’s control of Malmesbury. Robert of Gloucester took personal charge of the campaign against Malmesbury. He knew that taking the strong keep of Malmesbury by storm would be difficult. So he decided instead to starve the Malmesbury garrison into submission. Robert built three so-called siege castles around the town as bases for the siege. From these siege castles it would be possible to observe the town and castle and make sure that no food was allowed to enter and that none of Stephen’s soldiers were permitted to leave. It has long been thought that one of the bases established by Robert could be the substantial earthwork on Cam’s Hill, near Cowbridge, to the south of Malmesbury. In 2015 the University of Exeter published the results of a magnetometer and resistance surveys of the Cam’s Hill earthwork. The findings were consistent with the idea that Cam’s Hill was indeed one of Robert of Gloucester’s siege castles and was similar to other such structures from the period of the Anarchy. The resistivity survey identified archaeological remains that were possibly the foundations of an observation tower. The whereabouts of the other two siege castles is unknown,
The chronicle known as the Gesta Stephani gives a dramatic account of the siege of 1144. The chronicle described the rapid construction of the siege castles and immediate success in that the siege stopped Walter of Pinkney from sending out raiding parties. The siege lasted long enough for the garrison to be ‘in extremity of hunger’. It is evidence of the strategic importance of Malmesbury Castle to Stephen that he personally led a large force to end the siege of Malmesbury. On arrival at the town Stephen’s army broke up the besieging force and provided food supplies to the garrison. They then went on the offensive ravaging the lands around any castles loyal to Robert and Matilda. In 1145 Walter of Pinkney was captured by forces loyal to Matilda while outside the castle. He was tortured by Matilda but refused to change sides.
Matilda eventually retired and passed the baton to her son, Henry Plantagenet. In January 1153 Henry, the future Henry II, invaded England, intent on wresting the crown from Stephen. He landed in Dorset and his first act was to march deep inland and attack the castle of Malmesbury because it was loyal to his enemy, King Stephen, and strategically important. The town militia tried to stop the attackers but they were overwhelmed by Henry’s troops. The men of Malmesbury took refuge in the Abbey church but Henry’s soldiers burst in and massacred them and some of the monks. King Stephen heard of Henry’s presence in Malmesbury and brought his own army to the town. The two armies prepared to do battle but a dramatic storm disrupted the preparations and the leaders began to negotiate. They agreed to demolish the castle but Henry tricked Stephen and seized control of the castle, although through treachery rather than any military prowess. Stephen’s garrison commander changed sides and handed the castle over to Henry. and his triumph here paved the way for his accession to the throne of England one year later.
Malmesbury remained a royal castle after the civil war. There was no more fighting but the monks hated the presence of a rowdy castle garrison right next to their church. The monks got a chance to buy the castle towards the end of the reign of King John. In July 1215 King John was preparing for war and needed money. He agreed to sell the castle and much of the town of Malmesbury to Abbot Walter Loring.Things went badly for John in the year that followed the grant of 1215. On 21 May 1216 the heir to the French throne, Prince Louis, invaded England, and proceeded to take London. King John fled west. By 9 June he was in Devizes in Wiltshire and, desperate for money, he sold the right to Abbot Loring to demolish the castle. This was a moment of triumph for the monks and they immediately demolished the castle.