In the south range, parts of the medieval buildings survive and are incorporated into staircase ten — the straight, steep flight of stairs and timber-framed partitions date from a mid-15th century rebuilding of St Mary Hall. The former Chapel, Hall and Buttery of St Mary Hall, built in 1640, form part of the Junior Library and Junior Common Room. Viewed from Third Quad, the Chapel, with its Gothic windows, can be seen to have been built neatly on top of the Hall, a unique example in Oxford of such a plan.