April 12

240 – Shapur I becomes co-emperor of the Sasanian Empire with his father Ardashir I. 467 – Anthemius is elevated to Emperor of the Western Roman Empire. 627 – King Edwin of Northumbria is converted to Christianity by Paulinus, bishop of York. 1012 – Duke Oldřich of Bohemia deposes and blinds his brother Jaromír, who flees to Poland. 1204 – The Crusaders of the Fourth Crusade breach the walls of Constantinople and enter the city, which they completely occupy the following day. 1606 – The Union Flag is adopted as the flag of English and Scottish ships. 1776 – American Revolution: With the Halifax Resolves, the North Carolina Provincial Congress authorizes its Congressional delegation to vote for independence from Britain. 1807 – The Froberg mutiny on Malta ends when the remaining mutineers blow up the magazine of Fort Ricasoli. 1820 – Alexander Ypsilantis is declared leader of Filiki Eteria, a secret organization to overthrow Ottoman rule over Greece. 1831 – Soldiers marching on the Broughton Suspension Bridge in Manchester, England, cause it to collapse. 1861 – American Civil War: Battle of Fort Sumter. The war begins with Confederate forces firing on Fort Sumter, in the harbor of Charleston, South Carolina. 1862 – American Civil War: The Andrews Raid (the Great Locomotive Chase) occurs, starting from Big Shanty, Georgia (now Kennesaw). 1864 – American Civil War: The Battle of Fort Pillow: Confederate forces kill most of the African American soldiers that surrendered at Fort Pillow, Tennessee. 1865 – American Civil War: Mobile, Alabama, falls to the Union Army. 1877 – The United Kingdom annexes the Transvaal. 1900 – One day after its enactment by the Congress, President William McKinley signs the Foraker Act into law, giving Puerto Rico limited self-rule. 1910 – , one of the last pre-dreadnought battleships built by the Austro-Hungarian Navy, is launched. 1917 – World War I: Canadian forces successfully complete the taking of Vimy Ridge from the Germans.