Indian Ocean Monsoon Navigation

Timeline

1. c. -100–500India's west coast · IndiaThe Greek Periplus of the Erythraean Sea and Indian texts record western merchants using the monsoon to reach India's west coast from the Red Sea, marking the early systematization of seasonal Indian Ocean sailing knowledge.
2. c. 900–1030Basra and Baghdad · IraqScholars such as al-Mas'udi and Ibn Hawqal detailed the seasons of the southwest monsoon (kaws) and northeast monsoon (dabūr), specifying the months ships must depart and return; monsoon navigation became part of the Islamic world's maritime knowledge.
3. 1031–1040Aden–Quilon monsoon route · Arabian PeninsulaWhen the southwest monsoon rose each April–May, merchant ships sailed from Aden and Oman to India's west coast and Malabar; after the northeast monsoon arrived in October–November they returned to the Red Sea and Persian Gulf, with the Fatimid-controlled port of Aden in the 1030s serving as the core hub of this rhythm.
4. c. 1040–1300Strait of Malacca and East African coast · Southeast AsiaMonsoon sailing knowledge spread with Islamic merchants to the Bay of Bengal, the Strait of Malacca, and East Africa, forming a monsoon relay network linking the South China Sea, India, and Africa and providing the natural rhythmic foundation for Zheng He's voyages and later European East India Company routes.