Libraries In the early Church, as soon as churches began to be erected, it was customary to attach libraries to them. In these were included not only the liturgical and other Church books, and MS. copies of the holy Scriptures in the original languages, but also homilies and other theological works. That they were of some importance is evident from the manner in which they are referred to by Eusebius and Jerome, who mention having made use of the libraries at Jerusalem and Caesarea. Eusebius says he found the principal part of the materials for his Ecclesiastical History in the library at Jerusalem. One of the most famous was that attached to the church of St. Sophia, which is supposed to have been commenced by Constantine, but was afterwards greatly augmented by Theodosius the Younger, in whose time there were not fewer than one hundred thousand books in it, and a hundred and twenty thousand in the time of Basilicus and Zeno. No doubt a particular reason for thus collecting hooks was their great expense and rarity before the art of printing enabled men to possess themselves the works they needed for thorough research. In churches where the itinerant system prevailed libraries possessed by churches would even in our very day prove a source of pleasure, and timesaving as well. Indeed, in some of the larger cities here and there, cogregations are already advocating this plan.