"The curse, first widely noted in a Ripley's Believe It or Not book published in 1931, began with the death of William Henry Harrison, who died in 1841 after having been elected in 1840. For the next 120 years, presidents elected during years ending in a zero (occurring every 20 years) ultimately died while serving in office, from Harrison to John F. Kennedy (elected 1960, died 1963).
The name "Curse of Tippecanoe" derives from the 1811 battle. As governor of the Indiana Territory, William Harrison used questionable tactics in the negotiation of the 1809 Treaty of Fort Wayne with Native Americans, in which they ceded large tracts of land to the U.S. government. The treaty further angered the Shawnee leader Tecumseh, and brought government soldiers and Native Americans to the brink of war in a period known as Tecumseh's War. Tecumseh and his brother organized a group of Indian tribes designed to resist the westward expansion of the United States. In 1811, Tecumseh's forces, led by his brother, attacked Harrison's army in the Battle of Tippecanoe, earning Harrison fame and the nickname "Old Tippecanoe". Harrison strengthened his reputation even more by defeating the British at the Battle of the Thames during the War of 1812. In an account of the aftermath of the battle, Tecumseh's brother Tenskwatawa, known as the Prophet, supposedly set a curse against Harrison and future White House occupants who became president during years with the same end number as Harrison. This is the basis of the curse legend."