Ancient Greeks

The navigator and astronomer Phytheas were the first Greek to observe and explain ocean tides, in the Atlantic in the early third century BCE.  He was 2,000 years ahead of his time, for it took that long for tides to be attributed (by Newton) properly to the influence of the moon.  Until Newton's time, most scholars refused to believe that the moon could have any effect on the ocean, especially because one tide each day took place when the moon was not even visible in the sky.