Haha, wow. You really think that people who had little enough critical thinking skills that they believed the Earth was flat were so preoccupied with their agriculture-revolving lives that they didn't notice the ****ing incredible beauty of the night sky free of air and light pollution, that they weren't awed by it's mystery, and knew that it had no significance in their agricultural endeavors?
No, any human being who looks up at a clear night sky far from all the light that cities cast which obscure the star-filled sky in our civilization would be AWED by the sight, wonder what those lights are, and then immediately try to explain them. These explanations become superstitions, and they start connecting stars to see shapes in them. Then someone starts charting the positions of these stars, and notices that their positions change as time wears on.
Furthermore, it's blatantly obvious when a year has passed. Anyone who lives long enough will notice that a pattern of the seasons: cold winter gives way to warm, wet spring, gives way to dry hot summer, then chilly windy fall, and then back to winter. That is the basis by which the general time frame of a year come to be: in an attempt to better plan agricultural pursuits, finding out the average of how long each season is would be essential to producing an effective harvest.
