Administration in the relevant territories (Nueva Planta Decrees). Unlike Catalan, Basque was never a language written on official documents, but was equally affected. It lost ground to Castilian in all its buffer geographic areas, as well as main institutions as a communication language, after a number of decrees and orders established Castilian as "the national language of the Empire" during Charles III's reign; printing in languages other than Spanish was forbidden (1766), and Castilian was the only language taught in school (1768). The Peninsular War was followed by the centralization of Spain (Constitutions of 1812, 1837, 1845, 1856, etc.), with only the Basque districts keeping a separate status until 1876. Compulsory education in 1856 made the use of Castilian (Spanish) mandatory, as well as discouraging and forbidding the use of other languages in some social and institutional settings. Franco and his nationalist dictatorship imposed Spanish as the only valid language for any formal social interaction (1937). By the early 21st century, Spanish was the overwhelmingly dominant language in Spain, with Basque, Catalan, and Galician surviving and developing in their respective regions with different levels of recognition since 1980. Other minorized languages (Asturian, Aragonese) have also seen some recognition in the early 21st century. Catalan, sharing with Basque a strong link between language and identity, enjoys a fairly sound status. even though the setback of the social use of Catalan in the past decades has promoted the surge of new linguistic rhetorics such as the one by Mantinc el català. Basque competence has risen during the last decades, but daily use has not risen accordingly. The Endangered Languages Project has classified Asturian as being at risk and Aragonese as endangered. Taiwan Taiwanese aborigines used only Austronesian languages before other ethnic groups conquered Taiwan. After widespread migration of Han peoples from the 17th to the 19th century, many Taiwanese Plains Aborigines became Sinicized, and shifted their language use to other Sinitic tongues, (mainly Taiwanese Hokkien). Additionally, some Hakka people (a Han Chinese ethnic subgroup) also shifted from Hakka Chinese to Hokkien (also called Hoklo). This happened especially in Yongjing, Changhua, Xiluo, Yunlin, etc. They are called Hoklo-Hakka (Phak-fa-sṳ: Hok-ló-hak, Peh-oē-jī: Hô-ló-kheh, Hanzi: 福佬客). When Taiwan was under Japanese rule, Japanese became the official language, with the Japanese government promoting Japanese language education. It also led to the creation of Yilan Creole Japanese, a mixture of Japanese, Atayal language, and Hokkien in Yilan