Sextus Pompeius, a celebrated Latin grammarian of uncertain date, but who probably flourished in the third century of the Christian era. His celebrated work *De Verborum Significatione*, a valuable treatise on many obscure points of grammar, mythology, and antiquities, was an epitome of the voluminous work of M. Verrius Flaccus, a grammarian who flourished in the reign of Augustus. In compiling this abridgment Festus had made a few alterations, and inserted some critical remarks of his own, besides omitting altogether such ancient Latin words as had long been obsolete. These he discussed in a separate work now lost, entitled *Privrorum Verborum Libri cum Exemplis*. Of Flaccus' work only a few fragments have come down to us. Of Festus' epitome only one original copy is known to be in existence, and that in a very imperfect form. After passing through very many vicissitudes, it found a temporary shelter in the Farnese Library at Parma, whence in 1736 it was taken to Naples, where it now lies. At the close of the eighth century Paulus Diaconus, who happened to possess a copy of Festus' work, epitomized it; but as he was himself a poor scholar, he allowed countless errors to creep into his abridgment. From this work of his, and the solitary mutilated copy of the original which still survives, some of the most distinguished scholars of modern Europe have attempted to reconstruct the important treatise of Festus. Of the early editions the best are those of Scaliger, published in 1565, and of Fulvius in 1581, by both of which editors many of the blanks are filled up by conjecture. But by far the best of existing editions is that of K. O. Müller, Leipzig, 1839. Festus' work is in many respects extremely valuable. He gives not only the meaning of every word, but also its etymology; and this work, fragmentary as it is, has thrown much light on the language, mythology, and antiquities of ancient Rome.