Czech nationalism is a form of nationalism which asserts that Czechs are a nation and promotes the cultural unity of Czechs. Modern Czech nationalism arose in the 19th century in the form of the Czech National Revival. In 1848, Czech nationalism became an important political factor in the Austrian Empire due to the activities of the Old Czech Party, led by František Palacký. During World War I, Czech nationalist politicians, such as Karel Kramář in the Czech lands and Tomáš Garrigue Masaryk abroad, endorsed the idea of independence from Austro-Hungarian rule.