This division was formed as the result of the organization and redesignation of several other units. The 23d Marines began as infantry detached from the 3d Division in February 1943, the same month that an artillery battalion of the 12th Marines became the genesis of the 14th Marines and engineer elements of the 19th Marines formed the nucleus of the 20th Marines. In March the 24th Marines was organized, and then in May it was split in two to supply the men for the 25th Marines. This war-time shuffling provided the major building blocks for a new division. The units were originally separated, however, with the 24th Marines and a variety of reinforcing units (engineer, artillery, medical, motor transport, special weapons, tanks, etc.) at Camp Pendleton in California. The rest of the units were at Camp Lejeune, North Carolina. This East Coast echelon moved to Pendleton by train and transit of the Panama Canal in July and August. When all the units were finally together, the 4th Marine Division was formally activated on 14 August 1943. After intensive training, it shipped out on 13 January 1944, and in 13 short months made four major assault landings: Roi-Namur, Saipan, Tinian, and Iwo Jima, suffering more than 17,000 casualties. It was awarded two Presidential Unit Citations and a Navy Unit Commendation, and then deactivated 28 November 1945. In February 1966, however, it was reactivated as the lead division in the Marine Corps Reserve, and major units later served with distinction in the Persian Gulf. ] _The Marine Attack: Roi-Namur_ As the amphibian tractors sought to form up in organized attack waves, a series of problems arose. There was a continuation of the rough weather and radio communications difficulties of the day before; the amtrac crews had not previously practiced with the assault units; the control ship turned out to have been assigned firing missions as well as wave control and left its control station (followed by some stray amtracs); the attack commander was reduced to racing around in a small ship and shouting instructions through a megaphone. As a result, W-hour, the hour for attack, had to be postponed from 1000 to 1100.