What Happened on September 17 Calendar Major Events 642 Arab forces under Amr ibn al-'As conquer Alexandria 1683 Dutch scientist Antonie van Leeuwenhoek is the first to report the existence of bacteria Constitution of the United States 1787 The US Constitution is signed by delegates at the Philadelphia Convention

On Sept. 17, 1787, the Constitution of the United States was completed and signed by a majority of delegates attending the Constitutional Convention in Philadelphia.

On this day in 1787, the United States Constitution was signed by 39 delegates at the Constitutional Convention in Philadelphia. This monumental event laid the foundation for the American political system and became a model for democratic governance worldwide.

1978 Camp David Accords are signed The Camp David Accords were signed by Egyptian President Anwar El Sadat and Israeli Prime Minister Menachem Begin. The accords were the precursor to the 1974 Egypt-Israel Peace Treaty 1939 Man runs 10,000 meters in less than 30 minutes for the first time in recorded history