1864

1864 was a leap year in the Gregorian calendar. It was marked by ongoing global conflicts and constitutional developments that would shape the second half of the 19th century. In North America, the Civil War continued with major campaigns in the East and South. The Wilderness (May 5–7), Spotsylvania Court House (May 8–21), and Cold Harbor (May 31–June 12) featured intense fighting in Virginia. The Union siege of Petersburg began in June, while General William T. Sherman conducted the Atlanta Campaign, and Atlanta fell on September 2, 1864. Sherman then began his March to the Sea, culminating in the capture of Savannah on December 21, 1864. The year also included the Fort Pillow Massacre on April 12 and the Sand Creek Massacre on November 29. The U.S. presidential election held on November 8 resulted in the reelection of Abraham Lincoln on the National Union ticket with Andrew Johnson as vice president.

In international affairs, the Second Schleswig War between Denmark and the Prussian–Austrian alliance concluded in 1864. The Treaty of Vienna, signed on October 30, 1864, left Prussia and Austria in possession of the contested duchies of Schleswig and Holstein, reshaping northern European borders.

In China, the Taiping Rebellion was effectively ended around 1864 as Qing forces captured Nanjing and suppressed the movement, bringing one of the era’s largest civil conflicts to a close.

A landmark development in humanitarian law occurred with the adoption of the First Geneva Convention on August 22, 1864, which established protections for wounded soldiers and recognized neutral medical personnel on the battlefield.