Olympiad dating system
I suspect it might be in the form of "X years since the sack of Troy").
But since your question also asked about "ancient Roman scholars" and "ancient Roman sources"...
According to the Catholic Encyclopedia, even popes continued to date documents according to regnal years, and usage of AD only gradually became more common in Europe from the 11th to the 14th centuries.
In 1422, Portugal became the last Western European country to adopt the Anno Domini system.
Thus, they would have set the first Olympiad at the year we now call 776 b.c. In other words, they could date things as “such and such event occurred in the third year of the 95th Olympiad.” So it’s simple arithmetic to figure that date out: 95x4=380. As for telling the time of the day, the Ancients did what everybody else did until fairly recently, they observed the motion of celestial bodies: the sun, the moon, and stars.Students will demonstrate an understanding of the properties and evolution of stars and galaxies as well as their observation using different portions of the electromagnetic spectrum (e.g.Radio, Infrared, Visible, Ultraviolet, X-Ray and Gamma Ray).We have 12 hours of day and 12 hours of night (during the equinox) simply because the Ancient Babylonians used a base 12 number system.The Greeks (and later the Romans) simply followed the Babylonian “clock” system (though the Romans added a twist of changing how long the hours of day and night were to account for the shorter days or nights of winter and summer, respectively.)The Greeks had no mechanical clocks per se, but they did have a number of simple timers.