William Henry Harrison (February 9, 1773 – April 4, 1841) was the ninth President of the United States (1841), an American military officer and politician, and the first president to die in office. He was 68 years, 23 days old when inaugurated, the oldest president to take office until Ronald Reagan in 1981, and last President to be born before the United States Declaration of Independence. Harrison died on his 32nd day in office of complications from pneumonia, serving the shortest tenure in United States presidential history. His death sparked a brief constitutional crisis, but that crisis ultimately resolved many questions about presidential succession left unanswered by the Constitution until passage of the 25th Amendment.
Before election as president, Harrison served as the first territorial congressional delegate from the Northwest Territory, governor of the Indiana Territory and later as a U.S. representative and senator from Ohio. He originally gained national fame for leading U.S. forces against American Indians at the Battle of Tippecanoe in 1811, where he earned the nickname "Tippecanoe" (or "Old Tippecanoe"). As a general in the subsequent War of 1812, his most notable action was in the Battle of the Thames in 1813, which brought an end to hostilities in his region. This battle resulted in the death of Tecumseh and the disbandment of the Native American coalition which he led.