to be seen as a collective entity abroad; however, the persistence of language barriers, traditional strife between towns, and provincial particularism continued to form an impediment to more thorough unification. Following excessive taxation together with attempts at diminishing the traditional autonomy of the cities and estates in the Low Countries, followed by the religious oppression after being transferred to Habsburg Spain, the Dutch revolted, in what would become the Eighty Years' War. For the first time in their history, the Dutch established their independence from foreign rule. However, during the war it became apparent that the goal of liberating all the provinces and cities that had signed the Union of Utrecht, which roughly corresponded to the Dutch-speaking part of the Spanish Netherlands, was unreachable. The Northern provinces were free, but during the 1580s the South was recaptured by Spain, and, despite various attempts, the armies of the Republic were unable to expel them. In 1648, the Peace of Münster, ending the Eighty Years' War, acknowledged the independence of the Dutch Republic, but maintained Spanish control of the Southern Netherlands. Apart from a brief reunification from 1815 until 1830, within the United Kingdom of the Netherlands (which included the Francophones/Walloons) the Dutch have been separated from the Flemings to this day. Dutch Empire The Dutch colonial empire () comprised the overseas territories and trading posts controlled and administered by Dutch chartered companies (mainly the Dutch West India Company and the Dutch East India Company) and subsequently by the Dutch Republic (1581–1795), and by the modern Kingdom of the Netherlands after 1815. Ethnic identity The ideologies associated with (Romantic) Nationalism of the 19th and 20th centuries never really caught on in the Netherlands, and this, together with being a relatively mono-ethnic society up until the late 1950s, has led to a relatively obscure use of the terms nation and ethnicity as both were largely overlapping in practice. Today, despite other ethnicities making up 19.6% of the Netherlands' population, this obscurity continues in colloquial use, in which sometimes refers to the ethnic Dutch, sometimes to anyone possessing Dutch citizenship. In addition to this, many Dutch people will object to being called Hollanders as a national denominator on much the same grounds as many Welsh or Scots would object to being called English instead of British. The (re)definition of Dutch cultural identity has become a subject of public debate in recent years following the