American Civil War: The Trent Affair: Confederate diplomatic envoys James Murray Mason and John Slidell are freed by the United States government, thus easing tensions between the U.S. and the United Kingdom.

The American Civil War was a civil war in the United States between the Union and the Confederacy, which was formed in 1861 by states that had seceded from the Union. The central conflict leading to war was a dispute over whether slavery should be permitted to expand into the western territories, leading to more slave states, or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction.

The Trent Affair was a diplomatic incident in 1861 during the American Civil War that threatened a war between the United States and the United Kingdom. The U.S. Navy captured two Confederate envoys from a British Royal Mail steamer; the British government protested vigorously. American public and elite opinion strongly supported the seizure, but it worsened the economy and was ruining relations with the world's strongest economy and strongest navy. President Abraham Lincoln ended the crisis by releasing the envoys.

The Confederate States of America (CSA), also known as the Confederate States (C.S.), the Confederacy, or the South, was an unrecognized breakaway republic in the Southern United States from 1861 to 1865. It comprised eleven U.S. states that declared secession: South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia, Arkansas, Tennessee, and North Carolina. These states fought against the United States during the American Civil War.

James Murray Mason was an American lawyer and politician who became a Confederate diplomat. He served as U.S. Senator from Virginia for fourteen years, having previously represented Virginia's 15th congressional district in the U.S. House of Representatives, and Frederick County in the Virginia House of Delegates.