Illyria (Gk. niyris, Lat. Hlyricum), the name of a somewhat vaguely-defined country on the east shore of the Adriatic, where, according to legend, Cadmus of Thebes settled and became father of Illyrius, and so of the race or nation. Five Roman emperors had in their veins Ulyrian blood.
Gradually Ulyricum grew to be one of the four divisions of the empire, embracing a large share of the Balkan peninsula. On the split of the empire, it was partitioned into Illyria Romana and Illyria Grasca, and later on had to bear the brunt of Gothic and Slavonic invasion until the Huns amalgamated with the original population, and the coast as far as Dyrrachium was given up in the 7th century to the Slavs, who still occupy it. The Albanians, a branch of the old Illyrian stock, pushed farther south, but Illyria as a geographical appellation ceased to exist, Bosnia, Croatia, Servia, Dalmatia, and Rascia taking its place. Narenta and Ragusa for a time enjoyed great commercial prosperity, and in 1809 a kingdom of Illyria was revived by the Treaty of Vienna, but vanished from the map after forty years.