Teaching from books, where the teacher had a text but his pupils commonly had not, must have been practised in England at least from the time of Theodore of Tarsus and his school at Canterbury in the 670s. From the twelfth century onwards, the great variety of new schools for advanced teaching gradually settled into an articulated system, in which two emergent universities at Oxford and Cambridge were organized into faculties, and came to supply lectors to cathedral and monastic schools and schools of the friars. The earliest stage of this process, when some religious houses and cathedrals first recruited teachers educated in the schools of Paris or (less probably) Oxford, seems to have developed during the 1150s and 1160s: something of it may possibly be seen indirectly in the two early copies of Gratian’s Decretum acquired by Durham Priory not too long after its appearance, Durham Cathedral, ms. C. IV. 1, which has a list of questions and notabilia appended, and ms. C. II. 1, which carries an early copy of the standard gloss. But they cannot have been used to train the Durham monks in canon law in any formal way. A similar purpose may have caused Robert de Chesney, bishop of Lincoln (1148–66) to acquire his copy of the Sentences of Peter Lombard, a new standard textbook of theology, which is now Lincoln Cathedral, ms. 31. The bishop had been a scholar of Paris and probably taught in Oxford before 1145, but he cannot have acquired his copy before 1153, the date at which the work seems to have been completed.