It's harder than that. All the ancient peoples seem to have noticed the regularity of the moon first and developed a lunar calendar. The fact that this doesn't agree with the solar year was discovered soon enough and led to various schemes to reconcile the two. It also led to lunar-timed festivals wandering over the whole year, instead of being attached to a season as they might have been originally. As discovered later, over longer periods other adjustments had to be made, like the way we skip a leap day in years divisible by 400. Calculations based on the movements of planets were more dependable.There was also a way of measuring time in Jubilees, based on "weeks" of seven years. This is described in an apocryphal book called Jubilees, which is quite fascinating reading if you can keep the timelines straight, i.e. weeks of days vs. weeks of years. That calendar needed its own adjustment in a sort of leap day/year manner. The Book of Enoch also goes.into chronology. I recommend The Books of Enoch: The Angels, the Watchers and the Nephilim by Joseph Lumpkin for a description of Enochian chronology, he relates Enoch to the canonical Bible and other apocrypha as clearly as anyone could.