For centuries, jute has been an integral part of the culture of East Bengal and some parts of West Bengal, precisely in the southwest of Bangladesh. The British started trading in jute during the seventeenth century. During the reign of the British Empire, jute was also used in the military. British jute barons grew rich by processing jute and selling manufactured products made from it. Dundee Jute Barons and the British East India Company set up many jute mills in Bengal, and by 1895 jute industries in Bengal overtook the Scottish jute trade. Many Scots emigrated to Bengal to set up jute factories. More than a billion jute sandbags were exported from Bengal to the trenches of World War I, and to the southern United States for bagging cotton. It was used in the fishing, construction, art and the arms industries. Initially, due to its texture, it could only be processed by hand until someone in Dundee discovered that treating it with whale oil made it machine processable. The industry boomed throughout the eighteenth and nineteenth centuries ("jute weaver" was a recognised trade occupation in the 1900 UK census), but this trade had largely ceased by about 1970 due to the emergence of synthetic fibers. In the 21st century, jute again has become an important export crop around the world, mainly in Bangladesh.