When the idea of ​​decolonization is evoked, the usual image is a patriotic struggle fought by a dominated people against an imperial power to liberate their nation. In this perception, nationalist identity seems to be well defined, pre-existing the decolonization process and the main factor explaining it – but, in reality, it is not as simple as it seems. The essay will first discuss the contribution of nationalist factors, such as national identity and nationalist violence, and then investigate the impact of two important international factors: a war situation (against other great powers) and changing international norms regarding legitimacy of imperialism. The American Revolutionary War, the collapse of the Austro-Hungarian Empire, and the decolonization of Algeria and Angola will serve as case studies. The essay will show that the relative importance of these factors can vary, but will also argue that international factors are more decisive on the pace of the process, while nationalist factors are more significant when considering the outcome. In the case of the secession of the American Colonies, the colonists mostly came from the "mother country", thus sharing a common identity with the English they opposed. It could be argued that they differed because they were "independently minded men and women", even "rejecting the mother country in the very act of emigration", as argued by Daniel Boorstin, but they were undoubtedly British (Unit 17, p. 16). Most colonies had a governor, council, and assembly, which reflected British institutions (Unit 17, p. 18). Taxation was a source of discontent, but many colonists looked to the king to "protect [their] rights," as stated by the New York Assembly in 1764 (M...... half of document ..... .f the imperial state (Austria-Hungary), but the victorious allies can then interfere in the founding of the new nations. In the case of the decolonization of Algeria and Angola, changing international norms undermined imperial legitimacy, forcing the hand. to colonialism. Powers losing political support and prestige abroad. In conclusion, decolonization should rather be explained by a combination of nationalist and international factors – each of which strengthens the insurgents or weakens the capacity (or will) of the imperial power. to maintain its hold the factors can vary greatly, but international factors are much more decisive on the pace of the process breaking imperial superiority, while nationalist factors are more significant when considering the outcome favoring the creation of a viable nation.