The Corps of Discovery was a unit of the United States Army that was led by Meriwether Lewis and William Clark to explore the western region of the United States of America between 1804 and 1806. In 2376, Elias Vaughn, about to command the USS Defiant on an exploratory mission of the Gamma Quadrant, called on the crew to embrace the ideals of the Corps of Discovery during their journey. (DS9 - Mission Gamma novel: Twilight)