Philadelphia's importance and central location in the colonies made it a natural center for America's revolutionaries. By the 1750s, Philadelphia had surpassed Boston to become the largest city and busiest port in British America, and second in the British Empire, behind London. The city hosted the First Continental Congress before the American Revolutionary War; the Second Continental Congress, which signed the United States Declaration of Independence, during the war; and the Constitutional Convention (1787) after the war. Several battles were fought in and near Philadelphia as well.