Pennsylvania. The Continental Congress met there, the Declaration of Independence was signed there, and the Constitution was written there. For a while the United States Capitol was there. On this day, Dec. 12, 1787, Pennsylvania became the second state to join the union. The oath of office contained in Pennsylvania's Constitution read: "And each member [of the legislature], before he takes his seat, shall make ... the following declaration ... 'I do believe in one God, the Creator and Governour of the Universe, the Rewarder of the good and Punisher of the wicked, and I do acknowledge the Scriptures of the Old and New Testament to be given by Divine Inspiration.'"