"pertaining to or derived from Julius Caesar, 1590s, originally and especially in reference to the calendar system that began with his reforms in 46 B.C.E. (superseded by the Gregorian). The masc. proper name is from Latin Iulianus, from Iulius. The Julianists were a sect of Monophysites who held the body of Christ to be incorruptible; they were named for their leader, Julian, bishop of Halicarnassus (early 6c.).
Julian period, a period of 7,980 Julian years proposed by Joseph Scaliger in 1582 as a universal standard of comparison in chronology, consisting of the years of the solar and lunar cycles and the cycle of the indiction multiplied into each other (28 x 19 x 15). The first years of these cycles coincided in the year 4713 B.C., from which the period is reckoned. The first year of the Christian era being found by calculation to correspond to the year 4714 of the Julian period, all previous and subsequent comparisons can be made by simple subtraction or addition. This period is still used in the computations of chronologists and astronomers. [Century Dictionary, 1899]
late 12c., Giw, Jeu, "a Jew (ancient or modern), one of the Jewish race or religion," from Anglo-French iuw, Old French giu (Modern French Juif), from Latin Iudaeum (nominative Iudaeus), from Greek Ioudaios, from Aramaic (Semitic) jehudhai (Hebrew y'hudi) "a Jew," from Y'hudah "Judah," literally "celebrated," name of Jacob's fourth son and of the tribe descended from him.
Spelling with J- predominated from 16c. Replaced Old English Iudeas "the Jews," which is from Latin. As an offensive and opprobrious term, "person who seeks gain by sordid means," c. 1600. Jews' harp "simple mouth harp" is from 1580s, earlier Jews' trump (1540s); the connection with Jewishness is obscure, unless it is somehow biblical.
In uneducated times, inexplicable ancient artifacts were credited to Jews, based on the biblical chronology of history: such as Jews' money (1570s) "Roman coins found in England." In Greece, after Christianity had erased the memory of classical glory, ruins of pagan temples were called "Jews' castles," and in Cornwall, Jews' houses was the name for the remains of ancient tin-smelting works.