The Illyrian movement (, ) was a pan-South-Slavist 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 1835–1849 (there is some disagreement regarding the official dates). 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.