Roman emperor (285-305). Although he was the son of Dalmatian slaves (Eutropius, ix. 19), he rose to the highest honors by virtue of his personal qualities. The rabbinical sources have amplified the account of his lowly origin by reporting that he was a swineherd in his youth, even his original name, Diocles, being mentioned in this connection (Yer. Ter. 46c; Gen. R. lxiii. 8). According to these sources, he spent his youth in Palestine, where he was mocked by the Jewish school-boys; and after he became emperor the Jews agreed that not even the most insignificant Roman ought to be derided (ib.). According to the Talmud Yerushalmi, Diocletian went to Paneas in Palestine, where, not so much from cruelty as from a tyrannous impulse, he gave the patriarch Judah III. at Tiberias a command which was apparently impossible of fulfilment. Judah, however, succeeded in carrying it out, either through the cleverness of a servant or through magic (ib.).
Diocletian's presence in Palestine, which is often mentioned in rabbinical sources, is connected by Graetz with the Persian war of 297-298. This connection, however, is not necessary, for the fact is that Diocletian was in Palestine in 286, in the time of Judah III. (comp. Mommsen in "Verhandlungen der Berliner Akademie," 1860, pp. 417 et seq.). It is reported that he was at Cæsarea (Eusebius, "Vita Constantini," i. 19; compare Gen. R. lxiii. 8) and in the region of Tyre (Yer. Ber. 6a; Yer. Naz. 56a), which is not far distant from Paneas. At this lastnamed place, where Lake Phiala (Birkat-Ram) is situated, Diocletian built certain water-works, as may be inferred from the confused rabbinical notices (according to the correct reading in Yalk. to Ps. 697; compare Midr. Ps. xxiv. 6; Yer. Kil. 32c; Yer. Ket.. 35b; B. B. 74b), and the lake may possibly have been called for a time "Lake of Diocletian."
His stay in Palestine is memorable for the edict issued by him that sacrifices should be offered everywhere to the national gods, the Jews alone being exempted, for even the Samaritans obeyed the edict (Yer. 'Ab. Zarah 44d). The Christians also suffered heavily (Eusebius, "De Martyribus Palæstinæ," § 3); although the date 303-304, given by Eusebius for the issue of the edict, is different from that given by the Rabbis, who clearly assume that Diocletian was present in Palestine at the time. Diocletian endeavored to improve the pagan worship, as may be seen from an inscription preserved in the Talmud: "I, Emperor Diocletian, established this panegyric ofTyrus lasting eight days to the genius of my brother Herculius." "Herculius" was the surname of Maximian, Diocletian's associate emperor; Diocletian's surname was "Jovius." This inscription is valuable and significant as regards not only Diocletian, but also as evidence of the conditions in Palestine (Yer. 'Ab. Zarah 39b; compare Rapoport, "'Erek Millin," p. 230; I. Levi, in "Rev. Et. Juives," xliii. 196). It is also worthy of note that Diocletian led 120,000 men into Syria (Yer. Sheb. 34d), and that his measures were so severe that he drove the inhabitants of Paneas into exile, from which they returned after thirty years (Yer. Sheb. 38d). It is also said that Diocletian possessed a piece of virgin gold as large as a Gordianic denarius, and similar to that possessed by Hadrian (Num. R. xii. 4).
- Jost, Gesch. der Israeliten, iv. 172, 249, where Basnage, Histoire des Juifs (viii., ch. 3), is corrected;
- Grätz, Gesch. 3d ed., iv. 279;
- Kohut, "Aruch," Supplement, p. 49.