As important as missionaries were to the spread of Buddhism, traders played an even more crucial role in this process. Along with their products, traders carried Buddhism beyond India to Sri Lanka. Buddhist religion was also brought southeast along trade
routes to Burma, Thailand, and the island of Sumatra. Likewise, Buddhism followed the Central Asian trade routes, called the Silk Roads, all the way to China.
From China, Buddhism spread to Korea-and from Korea to Japan. The movement of trade thus succeeded in making Buddhism the most widespread religion
of East Asia. Throughout human history, trade has been a pow-
erful force for the spread of ideas.
What is the MAIN IDEA of the paragraph above?