The earliest painted glass preserved in the cathedral church of Wells— with the exception of the ten small tracery lights on the staircase leading to the chapter-house–belongs to the opening years of the fourteenth century. The reason for this is to be found in the history of the building. Begun under Bishop Reginald about the year 1186, it represents the period of transition between the Norman and the Early English styles. The thick walls with their straight buttresses are of the Norman type: the stout piers of the nave would betray the Norman heaviness, if each were not surrounded by four and twenty slender shafts. But, on the other hand, this is the first great church in England to banish wholly the round arch, which was still being used at Glastonbury for ornament where the structure did not require the new pointed form. In this transitional style Bishop Reginald's church was carried through to the end of the nave under Bishop Jocelin (1205-42), until the western wall was reached; and then, in the latter half of that great builder's time, we get quite suddenly the full perfection of the Early English in the elaborate splendour of the great west front.