Modern borders

The South West monsoon was key for the voyage from the West to India: Ships would leave Egypt in July in order to catch the wind bringing them safely into India in September. If the ship left earlier, in June, it would run the risk of arriving on India's west coast in August at which time conditions are very hazardous. The return voyage with the North East monsoon did not have to be so carefully timed although regular departure was in December-January.