1789 - Was the first time congress met under the new constitution. By Denelle Period: Jan 1, 1780 to Oct 13, 2011 Government Timeline Oct 13, 1789 1789 - Was the first time congress met under the new constitution. Oct 13, 1800 1800 - Congress permanently moves to bariks of potomac. Oct 13, 1811 1811 - Henry Clay was elected speaker of the house. Oct 13, 1812 1812 - Congress declared war for the first time. Oct 13, 1819 1819 - The Capitol got rebuilt. Mar 2, 1820 March 2,1820 - Congress passed the Missouri Compromise. Oct 13, 1850 1850 - There was 21,000 post offices. Oct 13, 1860 1860 - Abe Lincoln was elected President. Oct 13, 1861 1861 - The Civil War started. Oct 13, 1865 1865 - Abolishment of slavery. Oct 13, 1918 1918 - Was the declaration of war against Germany. Dec 7, 1941 Dec. 7th, 1941 - Japan attacked Pearl Harbor Oct 13, 1950 1955 - Began the Civil Rights movement.