The Silk Road was a Eurasian trade route that played a large role in global communication and interaction. It stimulated cultural exchange; encouraged the learning of new languages; resulted in the trade of many goods, such as silk, gold, and spices; and also spread religion and disease. It is even claimed by some historians – such as Andre Gunder Frank, William Hardy McNeill, Jerry H. Bentley, and Marshall Hodgson – that the Afro-Eurasian world was loosely united culturally, and that the Silk Road was fundamental to this unity. This major trade route began with the Han dynasty of China, connecting it to the Roman Empire and any regions in between or nearby. At this time, Central Asia exported horses, wool, and jade into China for the latter's silk; the Romans would trade for the Chinese commodity as well, offering wine in return. The Silk Road would often decline and rise again in trade from the Iron Age to the Postclassical Era. Following one such decline, it was reopened in Central Asia by Han Dynasty General Ban Chao during the 1st century.