 Prior to the creation of MARSOC, the Marine Corps had not been involved in special operations, which were conducted by Army, Navy and Air Force units assigned to U.S. Special Operations Command.After the September 11 attacks, the Secretary of Defense had directed the Marine Corps and Brown's predecessor to work closer together in the Global War on Terror.This culminated in the creation of MCSOCOM Detachment One on June 19, 2003, shortly before Brown took command of USSOCOM.