Richard Bickerton Pemell Lyons, 1st Earl Lyons was a British diplomat, who was the favourite diplomat of Queen Victoria, during the four great crises of the second half of the 19th century: Italian unification, the American Civil War, the Eastern Question, and the replacement of France by Germany as the dominant Continental power following the 1870 Franco-Prussian War. Lyons resolved the Trent Affair during the American Civil War; and contributed to the Special Relationship and to the Entente Cordiale; and for predicting, 32 years before World War I, the occurrence of an imperial war between France and Germany that was to destroy Britain's international dominance.

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.