The Trent Affair was a diplomatic incident in 1861 during the American Civil War that threatened a war between the United States and Great Britain. 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.

John Slidell was an American politician, lawyer, slaveholder, and businessman. A native of New York, Slidell moved to Louisiana as a young man and became a Representative and Senator. He was one of two Confederate diplomats captured by the United States Navy from the British ship RMS Trent in 1861 and later released. He was the older brother of Alexander Slidell Mackenzie, a U.S. naval officer.