The medical historian Ibn al-Qifṭī, writing in the first half of the thirteenth century, reports that a certain John the Grammarian was the Jacobite bishop in Alexandria when the Muslim general ‘Amr b. al-‘Āṣ conquered Egypt in the mid-seventh century. John had rejected the usual Christian beliefs about the Trinity – which we may suppose means the Greek Orthodox views – in favor of a doctrine that ‘Amr found more acceptable. When the Arabs seized the city,

John then explained that Ptolemy Philadelphus had established the library at great cost and effort, eventually accumulating 450,120 books. When his librarian told him that there nonetheless remained a great many more books in countries from India to Rome, Ptolemy was astonished and ordered him to continue collecting. Every ruler of Alexandria since that time had faithfully maintained the library's collection.