Trumpington proceeded to finish the work, and rebuilt five bays on the south side of the nave and four on the north. John de Cella's three deep porches are left to us in some small fragments; the rest is modern, and owes its erection to Lord Grimthorpe. The _Nave_ shows three periods of architecture. The eastern portion is the work of Paul de Caen (1077-1097). On the south side the three easternmost bays are Norman and were constructed by him. The next five bays are Decorated. These were begun by Abbot Hugh de Eversden (1308-1326), in whose time during Divine service two great piers on the south fell, and all the roof and beams of the south part were ruined. The rebuilding was finished by Abbot Michael de Mentmore (1335-1349). The four remaining bays are the Early English work of William de Trumpington (1214-1235). In Perpendicular times the roof of the aisle was lowered and made flat, disclosing the triforium openings, but in the recent restoration the original pitch has been renewed. On this side stood the cloister court, and against the south wall of the church are seen the remains of the arches of the north cloister walk. Part of the east walk cloister left its marks on the west wall of the south transept, but recent restoration has obliterated them. The south transept is Norman, the work of Paul de Caen, except the south wall, which has been entirely rebuilt by Lord Grimthorpe. The tall lancets are an imitation of "the Five Sisters" of York Minster. Turrets crowned with small caps stand at each angle of the transept. Below the window are the remains of the slype, or passage from the cloister to the monks' burial-ground. The south wall is all that remains of the chapter-house. On the east side of the transept were formerly two apsidal chapels, but all traces of these have been removed. They were destroyed in the time of Edward II. to make room for a sacristy. On the south of the south chancel aisle is a fine Norman arch leading to these apsidal chapels. When they were removed the arch was contracted by the insertion of a pointed arch. A vestry was constructed here in 1846.