The greater part of the present building is Transitional Norman, but there was much architectural activity in later periods. Owing to the fall of the tower and the action of an earthquake in 1248, much rebuilding was found necessary. The thirteenth century witnessed the reconstruction of the north transept, together with the building of the east chapels, which incline at so great an angle, much reparation of the choir, and the commencement of the Lady Chapel and eastern portion of the presbytery. During the Decorated period much work was accomplished. Bishop Martyn (1290-1328) finished the Lady Chapel, and Bishop Gower (1328-1347) did much for the fabric of the Cathedral, and built the noble Palace, which is still beautiful in decay. His work is seen in the upper portion of the walls of the nave and eastern part of the choir and presbytery, the inserted Decorated windows, the eastern chapel of the south transept, the alterations in the corresponding chapel of the north transept, the south porch, the second stage of the tower, and the famous rood-screen. During the fifteenth century and the latter years of the fourteenth century, new roofs were added, the south window in the south transept constructed, heavy buttresses placed against the north wall of the nave, which had shown signs of giving way, and during the early years of the sixteenth century the tower was raised, and a stone vault erected over the Lady Chapel and the chapels behind the high altar. During the Civil War sad havoc was wrought; lead was torn from the roof, and this caused the eastern chapels and the Lady Chapel to fall into decay. The once noble Cathedral, in consequence of the treatment which it received during the strife of King and Parliament, and of subsequent neglect, was shorn of its ancient glory, and ruin and desolation reigned. At the beginning of the nineteenth century some efforts were made to improve this state of things, and the west front was rebuilt in a debased and miserable style, and during the course of the century sundry alterations were made, and at length, in 1862, Sir G. Scott commenced a thorough restoration. Vast sums have been expended upon the fabric of the Cathedral, and though the eastern chapels remain in their ruined state, the rest of the building has been repaired and renewed, and preserved from destruction. "It remains," wrote Sir G. Scott, "a wonderfully interesting and valuable landmark in architectural history, taking in the extreme west a position parallel to that held by Canterbury in the extreme east of the island." THE EXTERIOR