ism. To this
period belong the essays on moral subjects, such as the denunciation of
various cities (Tarsus, Alexandria) for their immorality. Most pleasing
of all is the _Euboica_ (vii.), a description of the simple life of the
herdsmen and huntsmen of Euboea as contrasted with that of the
inhabitants of the towns. _Troica_ (xi.), an attempt to prove to the
inhabitants of Ilium that Homer was a liar and that Troy was never
taken, is a good example of a sophistical rhetorical exercise. Amongst
his lost works were attacks on philosophers and Domitian, and _Getica_
(wrongly attributed to Dio Cassius by Suidas), an account of the manners
and customs of the Getae, for which he had collected material on the
spot during his banishment. The style of Dio, who took Plato and
Xenophon especially as his models, is pure and refined, and on the whole
free from rhetorical exaggeration. With Plutarch he played an important
part in the revival of Greek literature at the end of the 1st century of
the Christian era.

Editions: J. J. Reiske (Leipzig, 1784); A. Emperius (Brunswick, 1844);
L. Dindorf (Leipzig, 1857), H. von Arnim (Berlin, 1893-1896). The
ancient authorities for his life are Philostratus, _Vit. Soph._ i. 7;
Photius, _Bibliotheca_, cod. 209; Suidas, s.v.; Synesius, [Greek:
Dion]. On Dio generally see H. von Arnim, _Leben und Werke des Dion
von Prusa_ (Berlin, 1898); C. Martha, _Les Moralistes sous l'empire
romain_ (1865); W. Christ, _Geschichte der griechischen Litteratur_
(1898), S 520; J. E. Sandys, _History of Classical Scholarship_ (2nd
ed., 1906); W. Schmid in Pauly-Wissowa's _Realencyclopadie_, v. pt. 1
(1905). The _Euboica_ has been abridged by J. P. Mahaffy in _The Greek
World under Roman Sway_ (1890), and there is a translation of _Select
Essays_ by Gilbert Wakefield (1800).

DIOCLETIAN (GAIUS AURELIUS VALERIUS DIOCLETIANUS) (A.D. 245-313), Roman
emperor 284-305, is said to have been born at Dioclea, near Salona, in
Dalmatia. His original name was Diocles. Of humble origin, he served
with high distinction and held important military commands under the
emperors Probus and Aurelian, and accompanied Carus to the Persian War.
After the death of Numerianus he was chosen emperor by the troops at
Chalcedon, on the 17th of September 284, and slew with his own hands
Arrius Aper, the praefect of the praetorians. He thus fulfilled the
prediction of a druidess of Gaul, that he would mount a throne