the compilations of Nonius and Macrobius, though it, too, goes back to good authorities, such as Varro. [Sidenote: Philosophy. Grammar.] The chief seat of philosophy in the fourth century was Athens, and philosophical writings were almost all in Greek. For the most part they expounded the mystical doctrines of Neoplatonism.[134] The grammarian Ælius Donatus, who flourished at Rome about 350 A. D. and was one of the teachers of St. Jerome, wrote commentaries on Terence and Virgil to which he prefixed the lives of the two poets from the lost work of Suetonius. The work on Virgil is lost, and the commentary on Terence contains in its present form many later additions. The extant grammars (_Ars Grammatica_) of Charisius and Diomedes, which have preserved much of the learning of earlier grammarians, belong to a very slightly later time. The last and most complete ancient grammar was written under the Emperor Anastasius (491-518 A. D.) at Constantinople in the Latin language by Priscian, from Cæsarea, in Mauretania. This work, in eighteen books, is entitled _Institutiones Grammaticæ_, and contains a vast quantity of material from the earlier literature. Much of the grammatical terminology, even of the present time, is derived from Priscian. The important commentary on Virgil by Servius was written in the latter part of the fourth century, and is preserved in two forms, in one of which numerous additions have been made to the original work.[135] [Sidenote: History.] In 360 A. D., Aurelius Victor wrote a short history of the emperors (_Cæsares_) from the time of Augustus to the tenth consulship of Constantius and Julian, i. e., to the date of his writing. He makes free use of Suetonius, and his style is sometimes an imitation of that of Sallust. A second entirely distinct work attributed to the same author is a brief epitome of the history of the emperors to the death of Theodosius I (395 A. D.). Under Valens (364-378 A. D.) Eutropius wrote a _Breviarium ab Urbe Condita_, a short sketch of Roman history from the beginning to the year 365 A. D., which is distinguished for its simple, easy style and pure Latinity, but has no independent value as an historical work.[136]