In 1861, the American Civil War began after many years of tension between the Northern and Southern states. The main reason for these tensions is said to be the debate over slavery between the North and South, and although some documents support this claim, it is false. The war had been brewing since 1607, even before slavery was introduced into the colonies that would become the United States of America. The debate over slavery played a major role in the Civil War; but he did so in support of the true cause of the Civil War. The primary cause of the American Civil War was not the debate over slavery, but rather Europe's role in the American economy. Europe's involvement in the American economy dates back to Marco Polo's expedition to China. In 1323, Marco Polo traveled to China, an obscure country for the majority of Europeans. Polo described China as "abundant with ginger, silk and poultry" and also stated that "there was a great abundance of silk and a large trade". Europe, ready to explore new lands and new resources of wealth, decided to establish flourishing trade with China. After years of successful trade, new conflicts arose when the Turkish Empire conquered Constantinople and the Eastern Mediterranean, allowing the powerful Empire to take control of all land routes leading to the Silk Road. Without access to the silk and spices they desired, Europe soon turned their interest elsewhere toward a trade route. In 1492, Spanish explorers set out on an expedition in search of a westward sea route to the Indies. The expedition was led by Italian explorer Christopher Columbus who landed in an "unknown and unexplored land" in which he believed to be the Indies, but which turned out to be the Americas. Columbus, believer... middle of paper ......historyisaweapon.com. http://www.historyisaweapon.com/defcon1/zinnvil3.html (accessed January 18, 2012). Borio, Gene. "A Brief History of Jamestown, Virginia." Tobacco.org. http://www.tobacco.org/History/Jamestown.html (accessed January 19, 2012). Scheeren, William O. “Invention of Cotton Gin.” ehistory.osu.edu. http://ehistory.osu.edu/osu/archive/articleview.cfm?aid=31 (accessed January 20, 2012). Schur, Joan B. "Eli Whitney's Patent for Cotton Gin." archives.gov. http://www.archives.gov/education/lessons/cotton-gin-patent (accessed January 22, 2012). Scheeren, William O. “Invention of Cotton Gin.” ehistory.osu.edu. “King Cotton Diplomacy – Its Aims and the Reasons for Its Failure.” world history online.org. http://www.worldhistoryonline.org/american-history/king-cotton-diplomacy-its-objectives-and-reasons-for-failure.html (accessed January 22, 2012).