The quarrel between Stephen and his bishops grew worse and worse. Roger of Salisbury died in 1139. The Bishop of Winchester demanded the See for his nephew. Again Waleram of Mellent thwarted the Church, and his request was refused. At the Whitsuntide festival (1141) held in London, but one bishop,[18] and that a foreign one, was with the court. The state of uncertain anarchy was becoming highly distasteful to Robert of Gloucester. An opportunity occurred of bringing matters to a crisis. Ranulph, the Earl of Chester, had hitherto played fast and loose with both parties, and the King had parted from him at Lincoln, which he possessed in right of his mother Lucia, believing him to be his partisan. But, a few days after his departure, Ranulph and his brother William of Roumare, surprised the castle, on which the King, who was a good soldier and very rapid in his movements, suddenly came back and besieged it. Ranulph escaped from the castle to Robert of Gloucester, who seized the occasion to bring on a pitched battle. With Ranulph, his own partisans, and the Welsh, he reached the Trent, passed it with some difficulty, and appeared suddenly before Lincoln. A great battle ensued, in which the victory fell to Gloucester, and Stephen was himself taken prisoner. [Sidenote: Matilda seeks help of the Church, and becomes Queen.] [Sidenote: Importance of the Londoners. 1141.] Of course this defeat somewhat changed the balance of affairs. Cornwall was regained for the Empress, and her influence reached eastward as far as Bedford and Nottingham. But she could not hope in any true sense to obtain the crown without the consent of the all-powerful Church. At once therefore negotiations were opened with Henry of Winchester. Having won his adherence, and with it that of the greater part of the bishops, she went from Gloucester, accompanied by the Bishop of Ely and other supporters, to Winchester. In an open plain without the city she swore to follow the advice of the Legate on Church matters. Her oath was attested by Milo, afterwards Earl of Hereford, Earl Gloucester, Brian Fitz-Count, and others. A council of the Church was held a few days after. The Legate addressed the assembly, and declared his adhesion to Matilda. It is to be observed that he waited a day to receive the citizens of London, who were “as it were nobles by reason of the magnitude of the city.” Both the Londoners and many of the nobility besought for the release of Stephen, but their request was refused, and many of the royal party executed. Having obtained the castle of Oxford from Robert of Oilli, Matilda proceeded to London; but there the haughtiness of her behaviour soon produced the ruin of her cause. [Sidenote: Matilda’s opportunity, but she offends both Church and Londoners.] [Sidenote: Consequent revolution of affairs.] [Sidenote: Gloucester taken prisoner, and exchanged for Stephen. 1142.]