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 last President born as a British subject. He was also 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. 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 its resolution left unsettled many questions following the presidential line of succession in regard to constitution up until the passage of the 25th Amendment in 1967. He was the grandfather of Benjamin Harrison, who was the 23rd President from 1889 to 1893.