The momentous question of slavery in the territories came up in Jefferson's administration. The institution was permitted in Mississippi, but the ordinance of 1787 was maintained in Indiana. The importation of slaves was prohibited after January 1, 1808. James Madison, a Republican, became President, in 1809. The Indians, under Tecumseh, attacked the Western settlers, but were defeated at Tippecanoe by William Henry Harrison in 1811. In the same year, Congress determined to break with England. Clay and Calhoun led the agitation. Madison acceded, and war was declared June 18, 1812. The Treaty of Ghent was signed on December 24, 1814. British commerce had been devastated. A voyage even from England to Ireland was made unsafe. The leading events of the War of 1812 were the unsuccessful invasion of Canada and surrender at Detroit, August 12, 1812; sea fight in which the "Constitution" took the "Guerriere," August 19th; sea fight in which the "United States" took the "Macedonian," October 25, 1813; defeat at Frenchtown, January 22nd; victory on Lake Erie, September 10th; loss of the "Chesapeake" to the "Shannon," June 1st; victory at Chippewa, July 5, 1814; victory at Lundy's Lane, July 15th; Lake Champlain, September 11th; British burned public buildings in Washington, August 25th; American defeated British at Baltimore, September 13th; American under Jackson defeated the British at New Orleans, December 23rd and 28th. Kentucky, Tennessee and Ohio, were admitted as states, in 1792, 1796, and 1803, respectively. In 1806, the federal government began a wagon road, from the Potomac River to the West through the Cumberland Gap. New York State finished the Erie Canal, in 1825. The population increased so rapidly, that six new states, west and south of the Allegheny Mountains, were admitted between 1812 and 1821. A serious conflict arose in 1820 over the admission of Missouri. The Missouri Compromise resulted in the prohibition of slavery in the Louisiana Purchase, north of 36° and 30' north latitude. Missouri was admitted in 1831, and Maine, as a free state, in 1820. With the passing of protective tariff measures in 1816 a readjustment of party lines took place. Protection brought over New England from Federalism to Republicanism. Henry Clay of Kentucky was the leading advocate of protection. Everybody was agreed upon this point in believing that tariff was to benefit all classes. This time was known as "The Era of Good Feeling." Spain ceded Florida to the United States for $5,000,000.00, throwing in claims in the Northwest, and the United States gave up her claim to Texas. The treaty was signed in 1819.