Question: When did the twin of Okinawa Prefecture become part of the United States?

full_context: Document 1: 51st state: Puerto Rico has been under U.S. sovereignty for over a century when it was ceded to the U.S. by Spain following the end of the Spanish–American War, and Puerto Ricans have been U.S. citizens since 1917. The island's ultimate status has not been determined as of 2012[update], its residents do not have voting representation in their federal government. Puerto Rico has limited representation in the U.S. Congress in the form of a Resident Commissioner, a delegate with limited no voting rights. Like the states, Puerto Rico has self-rule, a republican form of government organized pursuant to a constitution adopted by its people, and a bill of rights.
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: Ka Lae: Ka Lae (), also known as South Point, is the southernmost point of the Big Island of Hawaii and of the 50 United States. The Ka Lae area is registered as a National Historic Landmark District under the name South Point Complex. The area is also known for its strong ocean currents and winds and is the home of a wind farm.
Document 4: Aloha Festivals: The Aloha Festivals are an annual series of free cultural celebrations observed in the state of Hawaii in the United States. It is the only statewide cultural festival in the nation. Highlights include the presentation of the Royal Court, a ho'olaule'a in Waikiki, and the Floral Parade. Approximately 30,000 people volunteer to plan, organize, and provide labor for the Aloha Festivals each year. Their efforts entertain over 1,000,000 people from throughout the state and visitors from all over the world.
Document 5: 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 6: Hawaii (island): Hawaiʻi The Big Island Landsat mosaic, 1999 -- 2001 Location in the state of Hawaii Geography Location 19 ° 34 ′ N 155 ° 30 ′ W ﻿ / ﻿ 19.567 ° N 155.500 ° W ﻿ / 19.567; - 155.500 Archipelago Hawaiian Islands Area 4,028 sq mi (10,430 km) Area rank 75th, largest island in the United States - 1st Highest elevation 13,803 ft (4,207.2 m) Highest point Mauna Kea Administration United States State Hawaii Symbols Flower Red Pua Lehua (ʻOhiʻa blossom) Color ʻUlaʻula (red) Largest settlement Hilo Demographics Population 185,079 (2010) Pop. density 46 / sq mi (17.8 / km)
Document 7: 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 8: Archeological Sites at Kawela: Archeological Sites at Kawela are a number of archeological sites at or near the settlement of Kawela on the southern coast of Molokai, the northernmost of the islands of Maui County, Hawaii. It was the site of two battles in Hawaiian history.
Document 9: 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 10: Honolua, Hawaii: Honolua Bay, Mokuleia Bay and Lipoa Point are part of an area known as the ahupuaʻa of Honolua, located just north of Kapalua, West Maui in Maui County, Hawaii, United States. The area is a mix of agricultural and conservation land tended by the Maui Land & Pineapple Company in Lahaina, Hawaii, including coastline management. Honolua Bay and Mokuleia Bay comprise the Honolua-Mokuleia Marine Life Conservation District.
Document 11: 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 12: 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 13: 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 14: Hawaiian Islands: The Hawaiian Islands (Hawaiian: Mokupuni o Hawai'i) are an archipelago of eight major islands, several atolls, numerous smaller islets, and seamounts in the North Pacific Ocean, extending some 1,500 miles (2,400 kilometers) from the island of Hawai ʻi in the south to northernmost Kure Atoll. Formerly the group was known to Europeans and Americans as the ``Sandwich Islands '', a name chosen by James Cook in honor of the then First Lord of the Admiralty John Montagu, 4th Earl of Sandwich. The contemporary name is derived from the name of the largest island, Hawaii Island.
Document 15: Ryukyukoku Matsuri Daiko Hawaii: Ryukyukoku Matsuri Daiko Hawaii (琉球國祭り太鼓ハワイ支部) is a chapter of the Okinawan Eisā taiko ensemble Ryukyukoku Matsuri Daiko. Often called RMD Hawaii for short, the chapter has branches on Oahu, Kauai, Maui and the Big Island of Hawaii in Kohala and Waimea. The headquarters for the Hawaii chapter is on Oahu.
ground_truth: August 12, 1898
sub_queries: Okinawa Prefecture >> twinned administrative body Answer: Hawaii
when did Hawaii become a part of the united states Answer: August 12, 1898