Though very far from being as full as could be wished, the accounts of libraries in Rome are more numerous than any relating to libraries in other parts of the ancient world. Besides the collections of books made by private persons, which in one or two instances were generously opened to the public by the owner, there were the imperial libraries, and the more strictly public libraries. Among the emperors whose names are especially associated with the gathering and preservation of books are Augustus, Tiberius and Trajan. Julius Cæsar had formed a scheme for the establishment of a public library, but it is not clear whether it was ever carried out or no. Domitian, to replace the library in the Capitol, which had been destroyed, sent scholars abroad to collect manuscripts and to copy some of those at Alexandria. Under Constantine the Roman public libraries numbered twenty-nine, and were very frequently lodged in the temples.
Last in point of date come the libraries of Byzantium, the city which the Emperor Constantine in 330 A.D. made the capital of the eastern portion of the empire, and named after himself. He at once began to gather books there, and his successors followed his example. Thus various libraries were established, and those which survived the fires which occurred from time to time in the city, existed until its capture by the Turks in 1452. On this occasion, and also after the assault by the Crusaders in 1203, the libraries probably suffered. It is said, too, by some that Leo III. wantonly destroyed a large number of books, but the assertion cannot be proved. Among the lost treasures of Constantinople was "the only authentic copy" of the proceedings of the Council of Nice, held in 325 A.D. to deal with the Arian heresy.
The ultimate fate of the imperial library at Constantinople yet remains a problem. Some are of opinion that it was destroyed by Amurath IV., and that none but comparatively unimportant Arabic and other Oriental manuscripts make up the Sultan's library. Some believe that, in spite of repeated assertions to the contrary on the part of Turkish officials and others, there somewhere lies a secret hoard, neglected and uncared for, perhaps, but nevertheless existent, of ancient and valuable Greek manuscripts. The Seraglio has usually been considered to be the repository of this hoard, and access to the Seraglio is very difficult and almost impossible to obtain. In the year 1800 Professor Carlyle, during his travels in the East, took enormous pains and used every means in his power to reach the bottom of the mystery surrounding the Seraglio treasures. He was assured by every Turkish officer whom he consulted on the subject that no Greek manuscripts existed there; and when by dint of influence in high quarters and much patience and perseverance he at length gained permission to examine the Seraglio library, he found that it consisted chiefly of Arabic manuscripts, and contained not a single Greek, Latin, or Hebrew writing. The library, or such part of it as the Professor was shown, was approached through a mosque, and consisted of a small cruciform chamber, measuring only twelve yards at its greatest width. One arm of the cross served as an ante-chamber, and the other three contained the book-cases. The books were laid on their sides, one on the other, the ends outward. Their titles were written on the edges of the leaves.