So they would know when the rivers would flood.

So they know when to plant their beer plants.

LOLL!! Beer plants!!

With a calendar you can (very roughly) predict the weather. I assume farmers figured it out first. When to plant, when to store food for upcoming winter/dry season/etc.

What astounds me are the astronomical calendars created by ancient people. Who the heck noticed that Mars and Venus are predictable?

@Call_Me_Jay Ancient astronomers noted the daily shift in planetary appearance time and location in the sky and so a curious gazer started to take notes. Do that for a couple years, and you can begin to predict where the planets will be next month and when conjunctions will occur.

Don’t need to be a Magus to do that!

The prediction that always amazes me is how they figured out when eclipses will occur.

In an astronomy class I took in college he asked for volunteers to plot the heavens the way the ancients did.
After several nights of marking and plotting they realized that all the stars revolved around a cluster of stars, that basically stayed unchanging, and that’s when they recognized our solar system.

Stonehenge and before. So that is 5000 years ago and I wasn’t there !

Religious necessities such as Groundhog day and MY birthday.

I don’t know how or why they did it but I wish our generations had the level of curiousity they possessed in general!

@ragingloli So they know when to plant their beer plants.

With the first reinbeer at the astrological quincunx.

@Dutchess_III After several nights of marking and plotting they realized that all the stars revolved around a cluster of stars, that basically stayed unchanging, and that’s when they recognized our solar system.

Wow.

The Muslim calendar is strictly lunar, and because the motion of the moon does not sync with that of the earth, a given day on the calendar cycles through the seasons.

I wonder if commerce played a role in creating calendars. A contract could be drawn up saying that certain goods would be delivered by a specified date.