So Columbus sales in the time that most people believed that the earth was flat. I get how the kept track of hours using sundials etc. but how did they keep track of years. There's no definite thing that happens every year the same day to mark 365 days. My best guess would be something like new Grange but if anyone knows if really appreciate it if you told me a definite answer.🙂
Well, I was looking for old questions to reference while writing my own answer to this one, and found an answer to your question itself. See u/wotan_weevil's answer about defining a year in this thread.
The reason I went looking at all, is because Copernicus' ascertion that we lived in a heliocentric system (ie orbiting the sun) has much more to do with this question than anything to do with Columbus. In fact, the idea that anybody thought the Earth was flat in 1492 is a myth, the shape of the globe had been well established for thousands of years u/Gregory_K_Zhukov explains more about Columbus' actual conflict in this excellent post.