Indian Ocean · 1st century
2 ideas
An anonymous first-century account lists ports, goods, winds, and trading conditions along routes linking Roman Egypt, East Africa, Arabia, and India.
Traders needed to know who ruled each stretch of coast, whether a single king friendly to the empire, separate chiefs for every market town, or raiders. That knowledge decided where it was safe to drop anchor, as when ships moored off an island rather than near a mainland port to avoid attacks from the shore.
Long ocean voyages depended on the yearly monsoon winds, so the guide tells traders which month to leave port, not just which way to steer. Once sailors learned they could cross open water directly instead of hugging the coast, the timing of the wind became the key to the whole trade.