The caliph Omar, in reply, expressed a high sense of his important services, but reproved him for even mentioning the desire of the soldiery to plunder so rich a city, one of the greatest emporiums of the East. He charged him, therefore, most rigidly to watch over the rapacious propensities of his men; to prevent all pillage, violence, and waste; to collect and make out an account of all moneys, jewels, household furniture, and everything else that was valuable, to be appropriated toward defraying the expenses of this war of the faith. He ordered the tribute also, collected in the conquered country, to be treasured up at Alexandria for the supplies of the Moslem troops. The surrender of all Egypt followed the capture of its capital. A tribute of two ducats was laid on every male of mature age, besides a tax on all lands in proportion to their value, and the revenue which resulted to the Caliph is estimated at twelve millions of ducats. It is well known that Amru was a poet in his youth; and throughout all his campaigns he manifested an intelligent and inquiring spirit, if not more highly informed, at least more liberal and extended in its views than was usual among the early Moslem conquerors. He delighted, in his hours of leisure, to converse with learned men, and acquire through their means such knowledge as had been denied to him by the deficiency of his education. Such a companion he found at Alexandria in a native of the place, a Christian of the sect of the Jacobites, eminent for his philological researches, his commentaries on Moses and Aristotle, and his laborious treatises of various kinds, surnamed Philoponus, from his love of study, but commonly known by the name of John the Grammarian. An intimacy soon arose between the Arab conqueror and the Christian philologist; an intimacy honorable to Amru, but destined to be lamentable in its result to the cause of letters. In an evil hour, John the Grammarian, being encouraged by the favor shown him by the Arab general, revealed to him a treasure hitherto unnoticed, or rather unvalued, by the Moslem conquerors. This was a vast collection of books or manuscripts, since renowned in history as the Alexandrian Library. Perceiving that in taking an account of everything valuable in the city, and sealing up all its treasures, Amru had taken no notice of the books, John solicited that they might be given to him. Unfortunately the learned zeal of the Grammarian gave a consequence to the books in the eyes of Amru, and made him scrupulous of giving them away without permission of the Caliph. He forthwith wrote to Omar, stating the merits of John, and requesting to know whether the books might be given to him. The reply of Omar was laconic, but fatal. "The contents of those books," said he, "are in conformity with the _Koran_, or they are not. If they are, the _Koran_ is sufficient without them; if they are not, they are pernicious. Let them, therefore, be destroyed."