On the winter morning of Tuesday, November 7, 1189, the rebel forces of Miles of Gloucester approached the town of Worcester. Miles of Gloucester was part of the rebel army who opposed King Stephen, and his army came to Worcester to lay waste to it and burn it to the ground. According to John of Worcester — the only source that records the attack on the city — he and others were in the church and had just finished prime when Miles’ army approached.
… we were engaged in divine service in the church, and had already chanted prime, when behold a large and strong army which we had expected for many days, approached from the south … Fearful for the sanctuary’s treasures, we put on our albs, and, while the bells tolled, carried the relics of our most blessed patron Oswald outside in suppliant procession, and, as the enemy rushed from one gate to another, we bore them to the cemetery.
Miles’ army first attacked a strongpoint in the southern part of the city near the castle, but the men of Worcester beat them back, if only for a short time. The soldiers from Gloucester then shifted their focus to the northern part of the city, where there were less defenses, and they succeeded in breaking through and setting fire to many houses. Miles’ men managed to take many people prisoner, as well as carrying off a large number of oxen, sheep, and horses.
When Waleran de Beaumont (the Earl of worcester and Count of Meulan) arrived at his city six days later, he sought vengeance for what had been done to him, and so he gathered an army and marched on Sudeley, sacking the city and carrying off prisoners of his own and much plunder. Thus, according to John of Worcester, the earl “rendered evil for evil … and returned to Worcester the next day.”
Source:
The Chronicle of John of Worcester (primary source)