Brock, M. G.; Curthoys, M. C. (2000). The History of the University of Oxford, Volume VII, Part 2. Oxford University Press. p. 689. ISBN9780199510177. "Thomas Hariot of St Mary Hall was teaching mathematics to Walter Ralegh of Oriel."
The more recent date is for example given in the Victoria County History of the Counties of England, Oxfordshire Volume III (1954) p.124. In a modern work, such as the Oriel College Oxford, A short guide (2006), the year is given as 1350.