The Chinese took great interest in the safety of their trade products and extended the Great Wall of China to ensure the protection of the trade route. Trade on the Road played a significant role in the development of the civilizations of China, Korea, Japan, India, Iran, Afghanistan, Europe, the Horn of Africa and Arabia, opening long-distance political and economic relations between the civilizations. Though silk was the major trade item exported from China, many other goods were traded, as well as religions, syncretic philosophies, sciences, and technologies. Diseases, most notably plague, also spread along the Silk Road. In addition to economic trade, the Silk Road was a route for cultural trade among the civilizations along its network. Traders in ancient history included the Bactrians, Sogdians, Syrians, Jews, Arabs, Iranians, Turkmens, Chinese, Malays, Indians, Somalis, Greeks, Romans, Georgians, Armenians, and Azerbaijanis.