John Castell (a.k.a. John Castle[1]) (c. 1380 – 1426) was a Master of University College, Oxford,[2] and later a Chancellor of the University of Oxford.
Castell was a Fellow of University College. He became Master of the College circa 1408.[2] He also held preferment in the Diocese of York with his mastership.[1] In 1411, a sentence of excommunication was issued by the Archbishop of Canterbury, Thomas Arundel, against Castell, Fellows at the College — Robert Burton (later Master of the College), John Hamerton, and Adam Redyford — and the College as a whole, due to Lollardy leanings.[2] An appeal to the Pope against the excommunication was made by the bursar of the College, John Ryvell. Castell survived the controversy and continued as Master until 1420.