In the medieval schools the Bible and the Fathers of the Church together constituted the fundamental argument in theological speculation. They were the two auctoritates, though different in order and degree, upon which the whole structure of the Sacra Doctrina was built. ‘The foundation stones of the edifice, of which the masters in theology are the architects’, as bishop Grosseteste in a famous letter addressed to the regent-masters in theology at Oxford put it, ‘are the books of the Old and the New Testaments’. The authoritative interpreters of Holy Writ are the Fathers of the Church. It was, therefore, imperative that the Masters in Sacra Pagina should be familiar with both the biblical and patristic teaching. That they were deeply versed in Holy Scripture cannot be doubted. Their writings bear witness to their thorough knowledge of the Sacred Books. The Bible was the text-book of the faculty of theology, the beginning and the end of the whole theological course. And since it was their main duty to expound the Scriptures, the masters in Divinity were rightly styled Magistri in Sacra Pagina, or in Sacra Scriptura.