John Slidell rose to prominence as a Louisiana politician in the decades before the War Between the States. A lawyer who began his career as a businessman, he moved to New Orleans in 1819. He was elected to the U.S. House of Representatives in 1843. As a states-rights Democrat, he supported James K. Polk for the presidency in 1844 and assured him a Louisiana majority in the presidential election. Polk appointed Slidell Commissioner to Mexico, with instructions to settle the Texas-Mexico boundary dispute and purchase New Mexico and California. Slidell was elected to the Senate in 1853 and aligned himself with other pro-southern congressmen. For a brief time he was considered the most powerful man in the U.S. Senate. In the 1860 campaign, Slidell supported Democratic presidential candidate John C. Breckinridge. He remained a moderate until Abraham Lincoln's election pushed the southern states into seceding. Siding with the South, Slidell accepted a diplomatic appointment to represent the Confederacy in France. His arrival in Europe was delayed by the Trent Affair, when he and fellow diplomat James M. Mason were removed from a British-registered ship by the commander of a Federal vessel. In order to avoid a war with Britain, Lincoln had the two men released on 1 January 1862. Upon arriving in Europe, Slidell found the French sympathetic to the Confederate cause, but met with little success in securing extensive military aid or the Franco-Confederate Treaty of Alliance he sought. Slidell remained in France lobbying throughout the war. Though he was never able to accomplish a Franco-Confederate liaison, Slidell, through his political abilities and bolstered by his marriage to a Louisiana Creole woman, arranged Confederate financing through private French interests, the Erlanger Family. Dismayed by the defeat of the C.S.A. in 1865, Slidell and his family stayed in Paris. He never sought pardon from the Federal government for his Confederate service, dying in London, England, 29 July 1871. He is buried in the Saint Roman tomb in Villijuif, France. In 1888, John Slidell's son-in-law, Baron Erlanger, a financier and large landowner in Saint Tammany Parish, founded the city and named it Slidell.