February 27 – Russian troops fire upon a crowd in Warsaw protesting Russian rule over Poland, killing 5 protesters. February 28 – Colorado is organized as a United States territory. March 2 Nevada is organized as a United States territory. American Civil War: Texas is admitted to the Confederate States of America. March 3 (February 19 O.S.) – Emancipation reform of 1861: Serfdom is abolished in the Russian Empire. March 4 Abraham Lincoln is sworn in as the 16th president of the United States. American Civil War: The "Stars and Bars" is adopted as the flag of the Confederate States of America. March 10 – El Hadj Umar Tall seizes the city of Ségou, destroying the Bamana Empire of Mali. March 11 – American Civil War: The Constitution of the Confederate States of America is adopted. March 13 – Tsushima incident: The Russian corvette Posadnik arrives at Tsushima Island in the Korea Strait, Japan, provoking a reaction from the Japanese Shogunate. March 17 – Italian unification: The Kingdom of Italy is proclaimed by the new Parliament, with Victor Emmanuel II of Piedmont-Sardinia becoming its king. March 19 – The First Taranaki War ends in New Zealand. March 20 An earthquake completely destroys Mendoza, Argentina. Italian unification: The surrender of Civitella del Tronto ends the Kingdom of the Two Sicilies. March 21 – Alexander Stephens, Vice President of the Confederacy, gives the infamous Cornerstone Speech in Savannah, Georgia, in which he declares that slavery is the natural condition of blacks, and the foundation of the Confederacy. March 28 – Confederate Arizona: convention in present-day Tucson ratified the ordinance of secession of southern part of New Mexico Territory. March 30 – Discovery of the chemical elements: Sir William Crookes announces his discovery of thallium. April–June April 7 – A population census is taken in the United Kingdom. April 12 – The American Civil War begins with the bombardment of Fort Sumter, South Carolina. April 13 – American Civil War: Fort Sumter surrenders to Southern forces. April 15 – American Civil War: President Abraham Lincoln issues a Proclamation calling for 75,000 men to confront in the South, "combinations too powerful to be suppressed in the ordinary way". April 17 – American Civil War: The state of Virginia secedes from the Union. April 20 – American Civil War: Robert E. Lee resigns his commission in the United States Army, in order to command the