It most likely spread from Peking (China) down to Chittagong, India (probably through trade) and then went to Calcutta (India) and Ceylon then it spread up through the Persian Gulf (most likely through trade, as it was a trade route) and the place invaded into Persia and Arabia.
Another way it spread was from Peking (China) to Hangchow (China) and then to Sian (China) which eventually spread to Kashgar and Lake Issyk Kul, after that, it went to Samarkand (Persia), Baghdad and Saria, after it hit Baghdad, it went to Mecca (Arabia)