Gregorian adj.

masc. proper name, popular in England and Scotland by mid-12c. (Pope Gregory I sent the men who converted the English to Christianity), nativization of Late Latin Gregorius, literally "wakeful" (equivalent to Latin Vigilantius), from Greek gregorios, a derivative of gregoros "to be watchful," from PIE root *ger- (2) "to be awake" (source also of Sanskrit jagarti "he is awake," Avestan agarayeiti "wakes up, rouses"). At times confused with Latin gregarius (see gregarious).

"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Caesar, 1590s, originally and especially in reference to the calendar system that began with his reforms in 46 B.C.E. (superseded by the Gregorian).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]