The Early English builders began to build a new choir about 1200 A.D., of which only the lower part of the three westernmost bays and the sacristy on the south side remain. About 1220 they began to replace the Norman transepts with Early English work, beginning with the south transept and ending with the north. The nave was constructed about the middle of this century and central tower added, and the chapter-house belongs to the same period of architectural activity. In the last quarter of the century the west front was begun. At the end of the century a notable bishop was appointed, one Walter de Langton, Keeper of the Great Seal and Treasurer of England in the reign of Edward I., who incurred the hatred of Prince Edward, afterwards Edward II., and was several times imprisoned by him. He led a very stormy life, but found time to begin the building of the beautiful Lady Chapel at Lichfield, surrounded the close with a wall and a fosse, thus making it a fortress, erected a grand shrine for the relics of St. Chad and built the Palace. This chapel was finished by Bishop Northburgh, who had fought at Bannockburn and been taken prisoner by the Scots, and at the same time the presbytery and clerestory of the choir were rebuilt in the Decorated style. The church was now complete, and very perfect must it have been, glorious with the best achievements of true English Gothic art when that art was at its best. Quaint Thomas Fuller describes it as "the neatest pile in England," and tells us that Bishop Heyworth "deserved not ill of his Cathedral Church of Lichfield, which was in the vertical heights thereof, being, though not augmented in the essentials, beautified in the ornamentals thereof. Indeed the west front thereof is a stately fabric, adorned with exquisite imagery, of which I suspect our age is so far from being able to imitate the workmanship, that it understandeth not the history thereof." Quoting a saying of Charles V. of Florence, "that it was fit that so fair a city should have a case and cover for it to keep it from wind and weather," he adds, "so in some sort this fabric may seem to deserve a shelter to secure it." It was also a church rich in relics and costly ornaments, and kings and nobles loved to adorn it with bounteous offerings, while the shrine of St. Chad brought many a pilgrim to fill its treasury when they paid their vows. The fifteenth century made few alterations to the fabric. Dean Heywood built a library, which has now disappeared. Some Perpendicular windows were inserted.