Since the 7th century, the Minster has been at the centre of Christianity in the north of England. It is the seat of the Archbishop of York, the third-highest office of the Church of England. It was completed in 1472 after several centuries of building. It is devoted to Saint Peter, and has a very wide decorated gothic nave and chapter house, a perpendicular gothic quire and east end and early english North and South transepts. The nave contains the West Window, constructed in 1338, and over the Lady Chapel in the east end is the Great East Window (finished in 1408), the largest expanse of medieval stained glass in the world.