From catalogues of monastic libraries preserved in D'Achery's Spicelegium, it may be concluded that it was considered a large collection, when an abbey possessed from two to three hundred volumes. The rich abbey of Centule had such a collection, in the ninth century.[6] The mention of a library like this will give to some readers the idea of books having been more common in the dark ages than they had supposed; for there can be no doubt that the scarcity of books, at that period, has been somewhat exaggerated; but still, even a library of this extent, in a wealthy abbey, does not say much in proof of a large multiplication of manuscripts, and of great diligence on the part of monastic transcribers. The process of copying was, as every one must admit, tedious and expensive; but the Romans, the Egyptians, and the Saracens, had to contend with the same difficulties, yet their libraries were some of them prodigiously large. Seven hundred thousand volumes, it was calculated, were in the famous library of Alexandria: but that was beyond all parallel. The library of Pergamus, however, amounted to 200,000 volumes. Doubtless, many of the books of the ancients were small, for Ovid speaks of his fifteen books of Metamorphoses as forming an equal number of volumes;[7] yet, allowing for this, some of the libraries of antiquity must have been very extensive. Nor were very considerable libraries at all uncommon, in the houses of men of literary taste, before the fall of Rome. The libraries of the Saracens were also extremely large. That of the Fatimites consisted of 100,000 manuscripts; and that of the Ommiades, in Spain, amounted to 600,000. It would be unfair to place large public libraries, or the private collections of princes, in comparison with the library of a monastery; but still, when we see how the difficulty of multiplying books by the pen has been overcome in many instances, and when we look at the vast numbers of persons in Europe, during so many centuries, devoted to the monastic profession, their literary labours do not appear to have been very great.