Question: When did the state where Pearl Harbor is located become a part of the United States?

full_context: Document 1: Pacific War: Nishimura's force consisted of two battleships, one cruiser and four destroyers. Because they were observing radio silence, Nishimura was unable to synchronize with Shima and Kurita. Nishimura and Shima had failed to even coordinate their plans before the attacks – they were long-time rivals and neither wished to have anything to do with the other. When he entered the narrow Surigao Strait at about 02:00, Shima was 22 miles (40 km) behind him, and Kurita was still in the Sibuyan Sea, several hours from the beaches at Leyte. As they passed Panaon Island, Nishimura's force ran into a trap set for them by the U.S.-Australian 7th Fleet Support Force. R. Adm. Jesse Oldendorf had six battleships, four heavy cruisers, four light cruisers, 29 destroyers and 39 PT boats. To pass the strait and reach the landings, Nishimura had to run the gauntlet. At about 03:00 the Japanese battleship Fusō and three destroyers were hit by torpedoes and Fusō broke in two. At 03:50 the U.S. battleships opened fire. Radar fire control meant they could hit targets from a much greater distance than the Japanese. The battleship Yamashiro, a cruiser and a destroyer were crippled by 16-inch (406 mm) shells; Yamashiro sank at 04:19. Only one of Nishimura's force of seven ships survived the engagement. At 04:25 Shima's force of two cruisers and eight destroyers reached the battle. Seeing Fusō and believing her to be the wrecks of two battleships, Shima ordered a retreat, ending the last battleship-vs-battleship action in history.
Document 2: 51st state: Before Alaska and Hawaii became states of the United States in 1959, the corresponding expression was ``the 49th state ''.
Document 3: Philippines campaign (1941–1942): From mid-1941, following increased tension between Japan and several other powers, including the United States, Britain and the Netherlands, many countries in South East Asia and the Pacific began to prepare for the possibility of war. By December 1941, the combined defense forces in the Philippines were organized into the US Army Forces in the Far East (USAFFE), which eventually included the Philippine Army's 1st Regular Division, 2nd (Constabulary) Division, and 10 mobilized reserve divisions, and the United States Army's Philippine Department. General Douglas MacArthur was recalled from retirement by the U.S. War Department and named commander of USAFFE on 26 July 1941. MacArthur had retired in 1937 after two years as Military Advisor to the Philippine Commonwealth, and accepted control of the Philippine Army, tasked by the government of the Philippines with reforming an army made up primarily of reservists lacking equipment, training and organization.
Document 4: Attack on Pearl Harbor: The attack on Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service against the United States naval base at Pearl Harbor, Hawaii Territory, on the morning of December 7, 1941. The attack, also known as the Battle of Pearl Harbor, led to the United States' entry into World War II. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI, and as Operation Z during its planning.
Document 5: United States Pacific Fleet: A Pacific Fleet was created in 1907 when the Asiatic Squadron and the Pacific Squadron were combined. In 1910, the ships of the First Squadron were organized back into a separate Asiatic Fleet. The General Order 94 of 6 December 1922 organized the United States Fleet, with the Battle Fleet as the Pacific presence. Until May 1940, the Battle Fleet was stationed on the west coast of the United States (primarily at San Diego). During the summer of that year, as part of the U.S. response to Japanese expansionism, it was instructed to take an ``advanced ''position at Pearl Harbor, Hawaii. Long term basing at Pearl Harbor was so strongly opposed by the commander, Admiral James O. Richardson, that he personally protested in Washington. Political considerations were thought sufficiently important that he was relieved by Admiral Husband E. Kimmel, who was in command at the time of the attack on Pearl Harbor.
Document 6: Pacific War: President Franklin Roosevelt ordered General Douglas MacArthur in the Philippines to formulate a Pacific defence plan with Australia in March 1942. Curtin agreed to place Australian forces under the command of MacArthur who became Supreme Commander, South West Pacific. MacArthur moved his headquarters to Melbourne in March 1942 and American troops began massing in Australia. Enemy naval activity reached Sydney in late May 1942, when Japanese midget submarines launched a daring raid on Sydney Harbour. On 8 June 1942, two Japanese submarines briefly shelled Sydney's eastern suburbs and the city of Newcastle.
Document 7: Hawaii: Hawaii (English: / həˈwaɪ. i, - ji, - ʔi / (listen) hə - WY - (y) ee; Hawaiian: Hawai ʻi (həˈvɐjʔi)) is the 50th and most recent state to have joined the United States of America, having received statehood on August 21, 1959. Hawaii is the only U.S. state located in Oceania and the only one composed entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean. Hawaii is the only U.S. state located outside North America.
Document 8: History of Hawaii: The native population succumbed to disease brought by the Europeans (particularly smallpox), declining from 300,000 in the 1770s over 60,000 in the 1850s to 24,000 in 1920. Americans within the kingdom government rewrote the constitution, severely curtailing the power of King ``David ''Kalākaua, and disenfranchising the rights of most Native Hawaiians and Asian citizens to vote, through excessively high property and income requirements. This gave a sizeable advantage to plantation owners. Queen Liliuokalani attempted to restore royal powers in 1893, but was placed under house arrest by businessmen with help from the US military. Against the Queen's wishes, the Republic of Hawaii was formed for a short time. This government agreed on behalf of Hawaii to join the US in 1898 as the Territory of Hawaii. In 1959, the islands became the state of Hawaii of the United States.
Document 9: Hawaii: The Kingdom of Hawai ʻi was sovereign from 1810 until 1893 when the monarchy was overthrown by resident American and European capitalists and landholders. Hawaii was an independent republic from 1894 until August 12, 1898, when it officially became a territory of the United States. Hawaii was admitted as a U.S. state on August 21, 1959.
Document 10: Military history of the United States: Starting in 1940 (18 months before Pearl Harbor), the nation mobilized, giving high priority to air power. American involvement in World War II in 1940–41 was limited to providing war material and financial support to Britain, the Soviet Union, and the Republic of China. The U.S. entered officially on 8 December 1941 following the Japanese attack on Pearl Harbor, Hawaii. Japanese forces soon seized American, Dutch, and British possessions across the Pacific and Southeast Asia, except for Australia, which became a main American forward base along with Hawaii.
Document 11: United States Pacific Fleet: A Pacific Fleet was created in 1907 when the Asiatic Squadron and the Pacific Squadron were combined. In 1910, the ships of the First Squadron were organized back into a separate Asiatic Fleet.  The General Order 94 of 6 December 1922 organized the United States Fleet, with the Battle Fleet as the Pacific presence. Until May 1940, the Battle Fleet was stationed on the west coast of the United States (primarily at San Diego). During the summer of that year, as part of the U.S. response to Japanese expansionism, it was instructed to take an "advanced" position at Pearl Harbor, Hawaii. Long term basing at Pearl Harbor was so strongly opposed by the commander, Admiral James O. Richardson, that he personally protested in Washington. Political considerations were thought sufficiently important that he was relieved by Admiral Husband E. Kimmel, who was in command at the time of the attack on Pearl Harbor.
Document 12: Honolulu: In 1845, Kamehameha III moved the permanent capital of the Hawaiian Kingdom from Lahaina on Maui to Honolulu. He and the kings that followed him transformed Honolulu into a modern capital, erecting buildings such as St. Andrew's Cathedral, ʻIolani Palace, and Ali ʻiōlani Hale. At the same time, Honolulu became the center of commerce in the islands, with descendants of American missionaries establishing major businesses in downtown Honolulu.
Document 13: 51st state: Cuba, like many Spanish territories, wanted to break free from Spain. A pro-independence movement in Cuba was supported by the U.S., and Cuban guerrilla leaders wanted annexation to the United States, but Cuban revolutionary leader José Martí called for Cuban nationhood. When the U.S. battleship Maine sank in Havana Harbor, the U.S. blamed Spain and the Spanish–American War broke out in 1898. After the U.S. won, Spain relinquished claim of sovereignty over territories, including Cuba. The U.S. administered Cuba as a protectorate until 1902. Several decades later in 1959, the corrupt Cuban government of U.S.-backed Fulgencio Batista was overthrown by Fidel Castro. Castro installed a Marxist–Leninist government allied with the Soviet Union, which has been in power ever since.
Document 14: Overthrow of the Hawaiian Kingdom: The overthrow of the Kingdom of Hawaii began on January 17, 1893, with a coup d'état against Queen Liliuokalani on the island of Oahu by foreign residents residing in Honolulu, mostly United States citizens, and subjects of the Kingdom of Hawaii. They prevailed upon American minister John L. Stevens to call in the U.S. Marines to protect American interests, an action that effectively buttressed the rebellion. The revolutionaries established the Republic of Hawaii, but their ultimate goal was the annexation of the islands to the United States, which finally occurred in 1898.
Document 15: Naval Station Pearl Harbor: Naval Station Pearl Harbor is a U.S. naval base adjacent to Honolulu, in the U.S. state of Hawaii. In 2010, along with the United States Air Force's Hickam Air Force Base, the facility was merged to form Joint Base Pearl Harbor–Hickam.
ground_truth: August 12, 1898
sub_queries: What state is Pearl Harbor located in? Answer: Hawaii
when did Hawaii become a part of the united states Answer: August 12, 1898