and in the 20th century it was chosen as the National Day of Catalonia. After the War of the Spanish Succession, based on the political position of the Count-Duke of Olivares and the absolutism of Philip V, the assimilation of the Crown of Aragon by the Castilian Crown through the Decrees of Nova planta was the first step in the creation of the Spanish nation-state, with a centralised Spanish government. Like other contemporary European states, political union is the first step in the creation of the Spanish nation-state, in this case not on a uniform ethnic basis, but through the imposition of the political and cultural characteristics of the dominant ethnic group. in this case the Castilians, over those of other ethnic groups, become national minorities to be assimilated. In fact, since the political unification of 1714, Spanish assimilation policies towards Catalan-speaking territories (Catalonia, Valencia, the Balearic Islands, part of Aragon) and other national minorities have been a historical constant. It begins with secret instructions to the corregidores of the Catalan territory: "will take the utmost care to introduce the Castilian language, for which purpose he will give the most temperate and disguised measures so that the effect is achieved, without the care being noticed", and from there the actions, discreet or aggressive, are continued, and reach the last detail, such as, in 1799, the Royal Certificate prohibiting "represent, sing and dance pieces that were not in Spanish." These nationalist policies, sometimes very aggressive, and still in forces, have been and still are the seed of repeated territorial conflicts within the State. Although since its loss there are claims to recover the Furs, the beginnings of separatism in Catalonia can be traced back to the mid–19th century. The Renaixença (cultural renaissance), which aimed at the revival of the Catalan language and Catalan traditions, led to the development of Catalan nationalism and a desire for self-government, through a Spanish federal republic or even the independence. Between the 1850s and the 1910s, some individuals, organisations and political parties started demanding full independence of Catalonia from Spain. Twentieth century The first pro-independence political party in Catalonia was Estat Català (Catalan State), founded in 1922 by Francesc Macià. Estat Català went into exile in France during the dictatorship of Primo de Rivera (1923–1930), launching an unsuccessful uprising from Prats de Molló in 1926. In March 1931, following the overthrow of Primo de Rivera, Estat