Nationalism first emerged in the Middle Ages as the idea that nation-states had the right to self-rule if they were conquered by another power. Key figures like Napoleon Bonaparte and Otto von Bismarck helped spread nationalism and unite countries like Germany. Significant nationalist movements include India's independence from Britain, Ireland's movement to become independent from the UK, and Vietnam's fight against French colonial rule, many of which resulted in newly independent nation-states. Nationalism also caused conflicts and deaths but ultimately helped many groups gain independence and the rights to their own languages and religions.