Monsoon trade
Trade timed to the seasonal reversal of Indian Ocean winds, which carried ships to India and back.
Also: monsoon winds, Hippalus wind, seasonal sailing
The Indian Ocean monsoon blows from the southwest in summer and from the northeast in winter. Sailors learned to ride the southwest wind east from Arabia and East Africa to India, and return on the northeast wind, making regular round trips possible for dhows and, later, European ships. Roman accounts credit a pilot named Hippalus with revealing the route in the first century, though Arab and Indian sailors knew it earlier. Spice ships left Malabar by early winter and arrived in Muscat, Aden or Zanzibar a month or two later. The rhythm shaped ports, finance and ritual: pepper was gathered in the dry season, then loaded for the winds.