History attributes the best known mathematical astronomers to be the Mayans. (But were they merely riders on the storm?)

Their calendars use round numbers - 365, 260, 52.

When adjusting for leap years they subtracted 13 days from the 52 year cycle which creates a calendar that is way more accurate than ours. An error of only 1 day in 6729 years compared to our modern calendar which has an error of 1 day in 3236 years.