On this day in history, President John Tyler took the oath of office.
"[William Henry] Harrison's death made Tyler the first vice president to succeed to the presidency without being elected to the office. To forestall constitutional uncertainty, Tyler immediately took the oath of office, moved into the White House, and assumed full presidential powers, a precedent that would govern future successions and eventually become codified in the Twenty-fifth Amendment. A strict constructionist, Tyler found much of the Whig platform unconstitutional, and vetoed several of his party's bills."
At the time Tyler took over as President, there were no established rules as to how the Vice President was supposed to behave or even if he was supposed to govern at all (as opposed to being a place-holder until another President was elected). Tyler set the precedent for becoming the President.
Also, two of his grandchildren are STILL ALIVE! How cool is that?