William Henry Harrison (1773–1841) was the ninth President of the United States, an American military officer and politician, and the first president to die in office. He originally gained national fame for leading U.S. forces against American Indians at the Battle of Tippecanoe. As a general in the subsequent War of 1812, his victory at the Battle of the Thames brought an end to hostilities in his region. After the war, Harrison was elected to the United States Congress, later serving as a member of the Senate. Elected president in 1840, Harrison was the oldest president elected until Ronald Reagan, and the last President to be born before the United States Declaration of Independence. Harrison died in office of complications from pneumonia, having served 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.