Built in 1546, the college of Christ Church is referred to by its members as "The House." This is the site of Oxford's largest quadrangle, Tom Quad, named after the huge bell (6¼ tons) that hangs in the Christopher Wren–designed gate tower and rings 101 times at five past nine every evening in honor of the original number of Christ Church scholars. The vaulted, 800-year-old chapel in one corner has been Oxford's cathedral since the time of Henry VIII. The college's medieval dining hall, re-created for the Harry Potter films, contains portraits of many famous alumni, including 13 of Britain's prime ministers. Plan carefully, as the dining hall is only open weekdays 10:30–11:40 and 2:30–4:30 and weekends 2:30–4:30. Lewis Carroll, author of Alice in Wonderland, was a teacher of mathematics here for many years; a shop opposite the meadows on St. Aldate's sells Alice paraphernalia.