Eudoxus of Cyzicus
According to Poseidonius, in 118 BCE, the Greek navigator Eudoxus of Cyzicus led a voyage from Egypt to India, guided by a shipwrecked Indian sailor who had been rescued in the Red Sea and taken to Ptolemy VIII in Alexandria. He returned with a lucrative cargo of perfumes and precious stones, which Ptolemy promptly confiscated. Strabo's Geography repeats the story, and although the author doubted its veracity, modern scholars regard it as credible.
Regardless of its accuracy, Hippalus subsequently used the monsoons to cross the Arabian Sea to India rather than hugging the Arabian coast, and by 50 BCE, Greek and Roman ships used the monsoons to cross the Arabian Sea to India.
Eudoxus subsequently undertook a second voyage in 116, sailing without a guide. On the return leg of the journey, the wind forced him south of the Gulf of Aden onto the African coast, where he found the remains of a ship. Its appearance and local stories about the wreck led Eudoxus to conclude that the vessel came from Gades (Cádiz) and had sailed around Africa.
As a result, Eudoxus attempted to duplicate the feat, leaving Gades and working down Africa's western coast, trying to circumnavigate the continent. According to Pliny, he succeeded, but the consensus is that he probably died on the journey or was forced back to Egypt.
Links to add:
Poseidonius
Ptolemy VIII
Strabo
Arabian Sea
Gulf of Aden
Gades (Cádiz)
