Quid mihi Celsus agit? monitus multumque monendus Privatas ut quaerat opes, et tangere vitet Scripta Palatinus quaecunque recepit Apollo[42]. What is my friend Celsus about? he who has been reminded, and must still be reminded again and again, that he should draw upon his own resources, and be careful to avoid the multifarious writings which Palatine Apollo has taken under his charge. A man might say now-a-days, "Trust to your own wits, and don't go so often to the library of the British Museum." Aulus Gellius, who lived A.D. 117-180, speaks of "sitting with a party of friends in the library of the palace of Tiberius, when a book happened to be taken down with the title M. Catonis Nepotis," and they began asking one another who this M. Cato Nepos might be[43]. This library contained also public records[44]. The same writer tells a story of a grammatical difficulty which was to be settled by reference to a book _in templo Pacis_, in the forum of Vespasian; and again, when a particular book was wanted, "we hunted for it diligently," he says, "and, when we had found it in the temple of Peace, we read it[45]." The library in the forum of Trajan, often called _Bibliotheca Ulpia_, was apparently the Public Record Office of Rome. Aulus Gellius mentions that some decrees of former praetors had fallen in his way there when he was looking for something else, and that he had been allowed to read them[46]; and a statement of Vopiscus is still more conclusive as to the nature of its contents. It tells us, moreover, something about the arrangement. In his life of the Emperor Tacitus (Sept. A.D. 275--Apr. 276) Vopiscus says: And lest anybody should think that I have given too hasty a credence to a Greek or Latin author, the Ulpian Library has in its sixth press (_armarium_) an ivory volume (_librum elephantinum_) in which the following decree of the Senate, signed by Tacitus with his own hand, is recorded, etc.[47] Again, in his life of the Emperor Aurelian, the same writer records how his friend Junius Tiberianus, prefect of the city, had urged him to undertake the task, and had assured him that: "even the linen-books (_libri lintei_) shall be brought out of the Ulpian library for your use[48]."