Hippalus

Hippalus was an ancient Greek navigator and merchant who flourished in the 1st century BC Greece. In history he is credited for discovering the theory of the monsoons – namely, he found out that the wind blew steadily for six months from east to west, and the same amount of time in the opposite direction. Thanks to that discovery, the regular and flourishing trade by sea was developed connecting Egypt and the Graeco-Roman world with India. From Red Sea ports large ships crossed the Indian Ocean to the Tamil kingdoms of the Pandyas, Cholas and Cheras. It would last until the ascendance of Islam.

His discovery is described in the “Periplus Maris Erythraei” (Periplus of the Erythraean Sea), a work written in the 1st century. He also might have been the first Greek navigator to realize that the Indian coast runs from north to south and not from east to west.

After Hippalusu was named a crater on the moon.