The French Revolutionary Wars and the Napoleonic Wars had engulfed Europe since the early 1790s. Napoleon had won a decisive victory at the Battle of Austerlitz in 1805, and as a consequence Europe remained mostly at peace for the next few years, but tensions continued on the high seas, where the United States had long traded with both France and Britain. The United States benefited from these wars for much of the period prior to 1807, as American shipping expanded and Napoleon sold Louisiana Territory to the United States. In 1807, the British announced the Orders in Council, which called for a blockade on the French Empire. The French announced a policy that allowed for attacks on any American ships that visited British ports, but this policy had relatively little effect as Britain had established naval dominance at the 1805 Battle of Trafalgar. In response to subsequent British and French attacks on American shipping, the Jefferson administration had passed the Embargo Act of 1807, which cut off trade with Europe. Congress repealed this act shortly before Madison became president. In early 1809, Congress passed the Non-Intercourse Act, which opened trade with foreign powers other than France and Britain. Aside from U.S. trade with France, the central dispute between Great Britain and the United States was the impressment of sailors by the British. During the long and expensive war against France, many British citizens were forced by their own government to join the navy, and many of these conscripts defected to U.S. merchant ships. Unable to tolerate this loss of manpower, the British seized several U.S. ships and forced captured crewmen, some of whom were not in fact not British subjects, to serve in the British navy. Though Americans were outraged by this impressment, they also refused to take steps to limit it, such as refusing to hire British subjects. For economic reasons, American merchants preferred impressment to giving up their right to hire British sailors.