The troops under these leaders laid siege to the episcopal palace, which stood in the heart of the city. The bishop's garrison having set fire to the adjoining houses, which might have served as places of defence to the assailants, retired into their fortress, and waited for succour. Meanwhile the Bishop of Winchester had received an accession of strength from the troops of Queen Maud, among whom were the citizens of London, to the number, as already mentioned, of one thousand. Marching rapidly to Winchester, the bishop surprised the troops of the empress, who were compelled to entrench themselves in the churches, while Matilda herself, with her chief nobles, took refuge in the castle. Thus besiegers were in turn besieged; the sanctuary was not respected by the warlike Bishop of Winchester, and the churches were burnt down in order to force the occupants from their places of refuge. The unhappy inhabitants suffered extreme misery while this murderous warfare was going on in their streets; they were plundered by both of the opposing factions, their goods seized without redress, and their homes burnt down or ransacked. The castle, which was completely surrounded by the troops of the bishop, sustained a siege of six weeks, by which time the provisions of the garrison were exhausted. A daring expedient was determined upon by the empress as the alternative of an unconditional surrender. The 14th of September, 1141, was the feast of the Holy Rood or Cross, on which, as on other festivals of the church, it was the custom for antagonists in the field to desist from hostilities. At daybreak on that day, when the besieging troops were asleep or engaged in preparing for their devotions, Matilda stole out from the castle, accompanied by her brother, the Earl of Gloucester, and a small but chosen escort. Mounted on fleet horses they made their way through the troops of the bishop, and fled at full speed along the road to Devizes. A hot pursuit was immediately set on foot, and the fugitives were overtaken in the neighbourhood of Stourbridge. Finding escape impossible, the Earl of Gloucester and the knights who were with him turned upon their pursuers and kept them at bay, while the empress urged on her horse and arrived in safety at Devizes. After a gallant resistance the earl and several of his companions were taken prisoners. About a month after the capture of the Earl of Gloucester, a treaty was concluded between the belligerents, by the terms of which the king was exchanged for the earl, and thus the leaders of both armies regained their liberty. Stephen resumed his title and the exercise of the royal authority over the eastern and midland counties, which were the parts of the country in the possession of his adherents. Normandy no longer acknowledged the rule of the English king. During his imprisonment the duchy had submitted to Geoffrey of Anjou, who soon afterwards resigned it in favour of his eldest son Henry.