The Illyrian movement (Илирски покрет; Ilirsko gibanje) was a pan-South-Slavic cultural and political campaign with roots in the early modern period, and revived by a group of young Croatian intellectuals during the first half of the 19th century, around the years of 1835–1863 (there is some disagreement regarding the official dates from 1835 to 1870). This movement aimed to create a Croatian national establishment in Austria-Hungary through linguistic and ethnic unity, and through it lay the foundation for cultural and linguistic unification of all South Slavs under the revived umbrella term Illyrian.
Aspects of the movement pertaining to the development of Croatian culture are considered in Croatian historiography to be part of the Croatian national revival (Hrvatski narodni preporod).
In the 19th century, the name Illyrian was chosen by the members of the movement as a reference to the theory according to which South Slavs descend from ancient Illyrians. Fearing provincial particularism, reformers believed that the Illyrian name would make it easier to implement literary unity. The name Illyrian (Slavic) had already been used in reference to the South Slavic dialects spoken there at the time.
In 19th-century Europe, liberalism and nationalism were ideologies which came to the forefront of political culture. In Central Europe, where the Habsburg Empire had long asserted control over a variety of ethnic and cultural groups, nationalism appeared in a standard format. The beginning of the 19th century "was the period when the smaller, mostly Slavic nationalities of the empire – Czechs, Slovaks, Slovenes, Croats, and Serbs – remembered their historical traditions, revived their native languages as literary languages, reappropriated their traditions and folklore, in short reasserted their existence as nations." This revival of national heritage encompasses the Illyrian Movement in Croatia.
In 1813, the bishop of Zagreb, Maksimilijan Vrhovac, issued a plea for the collection of "national treasures" (Poziv na sve duhovne pastire svoje biskupije), thereby heralding the national revival movement.