A Year, a Day and a Month Are Not the Same

There are three events which we just happen to use to measure time, but none of them fit neatly and evenly into the others. A year was the period from one summer solstice to the next. Everyone used these same celestial events to keep track of time. So why couldn't they all get on the same page, the same calendar page in this case? Well, part of the answer is because these three celestial events, an astronomical day, an astronomical month and an astronomical year, don't divide evenly. Into each other.