I never miss an opportunity to post about my alma mater. The Siege of Oxford in 1142 was one of the most dramatic episodes of the civil war between King Stephen and Empress Matilda, a conflict remembered as the Anarchy. It was also a moment when the struggle for the English crown came remarkably close to being decided. Had Stephen succeeded in capturing Matilda at Oxford, the course of English history might have been very different.
The roots of the conflict lay in the death of Henry I in 1135. Henry had designated his daughter Matilda as his heir, but his nephew Stephen of Blois seized the throne and was crowned king. Matilda refused to accept his rule and, supported by her husband Geoffrey of Anjou and her half-brother Robert, Earl of Gloucester, fought to establish her own claim.
By 1141 Matilda had achieved a remarkable reversal of fortune. Stephen had been captured at the Battle of Lincoln and imprisoned, while Matilda’s supporters briefly controlled much of the kingdom. She adopted the title Lady of the English and appeared to be on the verge of becoming England’s first reigning queen. Yet her triumph was short-lived. She alienated London, was forced to withdraw, and eventually exchanged the captive Stephen for her own half-brother Robert, who had fallen into Stephen’s hands.
Stephen was therefore once again free—and determined to destroy Matilda’s cause.
During 1142 he gathered an army and moved against Matilda’s strongholds. Oxford was particularly important. The city was strategically situated in the Thames Valley and was strongly associated with Matilda’s party. Matilda herself had established her headquarters there, with Oxford Castle providing a formidable refuge.
Stephen approached Oxford on the 16th of September, 1142. According to contemporary accounts, his attack was sudden. His forces crossed the waterways around the city, reportedly with Stephen himself taking part in the hazardous crossing. The royal army captured Oxford itself, while Matilda and her supporters withdrew into the castle. The surrounding town suffered badly, with parts of Oxford burned during the fighting.
Oxford Castle was a substantial Norman fortress, with its great stone keep—St George’s Tower—providing the defenders with a powerful stronghold. Stephen realised that storming it would be difficult and costly. Instead, he settled down to besiege it.
The strategy was straightforward: prevent supplies and reinforcements from reaching the garrison and wait for hunger to force a surrender. For approximately three months Matilda and her followers endured the blockade. Conditions inside the castle steadily deteriorated. Food became scarce, while the besieging army maintained its positions around the fortress.
Stephen appeared to have achieved what he had wanted from the beginning. If Matilda could be captured, the Angevin cause might collapse. Then came one of the most famous escapes in English history.
In December, with winter tightening its grip on Oxford, heavy snow covered the ground. Matilda and a small group of companions decided that remaining inside the castle was becoming more dangerous than attempting to break through the siege. On a winter night she slipped out with four knights.
Exactly how they escaped is uncertain. Later chroniclers provided different accounts. One tradition says that Matilda was lowered from the castle walls by ropes; another suggests that she left through a postern gate. The famous detail that she wore white clothing or a white cloak is also recorded by medieval chroniclers, who said that it helped her blend into the snowy landscape.
Whatever the precise details, the escape was extraordinarily dangerous. Matilda and her companions passed through or around Stephen’s siege lines while the royal army remained unaware of their movements. They then crossed the frozen waters of the Thames or its associated channels and struggled through the snow towards safety.
Eventually Matilda reached the safety of the Angevin stronghold at Wallingford. The Oxford garrison, now deprived of its leader, surrendered to Stephen shortly afterwards.
The siege was therefore technically a victory for Stephen. He captured Oxford and its castle, but he failed in his principal objective: Matilda herself escaped. Her survival meant that the civil war continued.
The escape also acquired an almost legendary reputation. Medieval chroniclers treated Matilda’s survival as remarkable, even miraculous, although modern historians are understandably cautious about the more romantic details. The episode nevertheless demonstrated her determination and the resourcefulness of her supporters.
The Anarchy would continue for another decade. Neither Stephen nor Matilda could secure an outright victory. Ultimately the struggle was resolved not by the triumph of either claimant but through the next generation. Matilda’s son, Henry of Anjou, emerged as the future of the Angevin cause. In 1153 Stephen agreed that Henry would succeed him, and when Stephen died the following year, Henry became Henry II.
Thus the Siege of Oxford was much more than a local military operation. It was one of the pivotal episodes of the Anarchy: Stephen won the castle, but Matilda escaped; and by escaping, she preserved the dynastic struggle that eventually placed her son on the English throne.