The British mail steamer stopped by the U.S. Navy in the 1861 Trent Affair was RMS Trent.
On November 8, 1861, Union Captain Charles Wilkes used USS San Jacinto to intercept Trent in the Bahama Channel. Two Confederate diplomats, James Mason and John Slidell, were traveling aboard the British ship toward Europe, where they hoped to seek diplomatic recognition and support for the Confederacy. Wilkes removed them from the vessel and took them into custody.
The seizure triggered an international crisis because Trent was a neutral British mail packet, not a Confederate warship. Britain demanded the envoys’ release and prepared military reinforcements for Canada, while many people in the Union initially celebrated Wilkes’s action. President Lincoln and Secretary of State William Seward eventually decided that keeping the prisoners risked war with Britain.
The envoys were released in December 1861 and later continued to Europe. The incident is also called the Mason–Slidell Affair. The ship’s name is commonly confused with the diplomats’ names or with USS San Jacinto, the Union vessel that made the capture.