The Eastern Defense Command was first established as the Northeast Defense Command on 17 March 1941 as one of four U.S. Army continental defense commands to plan and prepare for and execute defense against enemy attack in the months before America's entry into World War II. Its mission was defined as: "a territorial agency with appropriate staff designed to coordinate or prepare to initiate the execution of all plans for the employment of Army Forces and installations against enemy action in that portion of the United States lying within the command boundaries." This organization was charged with coordinating the defense of the Atlantic Coast, replacing the New England Defense Sector, an organization of the U.S. First Army. However, this did not initially occur, and the command was little more than a planning agency until 24 December 1941.