Averroes regards as the law of Nature, bought a few books of Speusippus straightway after his death for seventy-two thousand sesterces. Plato, before him in time, but after him in learning, bought the book of Philolaus the Pythagorean, from which he is said to have taken the Timæus, for ten thousand denaries, as Aulus Gellius relates in the Noctes Atticæ. Now Aulus Gellius relates this that the foolish may consider how wise men despise money in comparison with books. And on the other hand, that we may know that folly and pride go together, let us here relate the folly of Tarquin the Proud in despising books, as also related by Aulus Gellius. An old woman, utterly unknown, is said to have come to Tarquin the Proud, the seventh King of Rome, offering to sell nine books in which (as she declared) sacred oracles were contained; but she asked an immense sum for them, insomuch that the king said she was mad. In anger she flung three books into the fire, and still asked the same price for the rest. When the king refused it, again she flung three others into the fire, and still asked the same price for the three that were left. At last, astonished beyond measure, Tarquin was glad to pay for three books the same price for which he might have bought nine. The old woman straightway disappeared, and was never seen before or after. These were the Sibylline books....”
The destruction of libraries, which was common in the Middle Ages, naturally caused an increase in the value of those which remained. How completely these libraries passed away may be seen by the instance of that which was once preserved in St. Paul’s Cathedral, and is noticed by the late Dr. Sparrow Simpson in his “St. Paul’s Cathedral Library” (1893). Walter Shiryngton Clerk founded the library, the catalogue of which (1458) fills eight folio pages in the first edition of Dugdale’s “History of St. Paul’s.” Of all the manuscripts in this catalogue, only three are now known to exist: one is still at St. Paul’s, the second is at Aberdeen, and the third at Lambeth.