Volcano Islands uninhabited. The first recorded sighting by Europeans was in October 1543 by Spanish navigator Bernardo de la Torre on board of carrack "San Juan de Letrán" when trying to return from Sarangani to New Spain. Iwo Jima was charted as Sufre, the old Spanish term for sulphur. The islands were uninhabited until 1889, when the two northern islands were settled by Japanese settlers from the Izu Islands. They were annexed by Japan in 1891. The population was about 1,100 in 1939, distributed among five settlements: Higashi, Minami, Nishi, Kita and Motoyama (meaning "East", "South", "West", "North" and "Mountain of Origin",
Japanese air attacks on the Mariana Islands Pagan. The Japanese were unable to use most of these bases, however, as they had been isolated and heavily damaged by United States air attacks, and the Imperial Japanese Army Air Force (IJAAF) and Imperial Japanese Navy (IJN) had relatively few aircraft and pilots available. Despite the limited threat of attack, the United States military took steps to protect the B-29 bases in the Mariana Islands. The USAAF's Seventh Air Force played the most important role, and continuously attacked the Japanese-held islands until just before the end of the war. United States Navy (USN) and United States Marine Corps (USMC)