Illyrcum
or Illris, more rarely Illyria (τὸ Ἰλλυρικόν, Ἰλλυρίς, Ἰλλυρία), included, in its widest signification, all the land west of Macedonia and east of Italy and Rhaetia, extending south as far as Epirus, and north as far as the valleys of the Savus and Dravus, and the junction of these rivers with the Danube. This wide extent of country was inhabited by numerous Illyrian tribes, all of whom were more or less barbarous. They were probably of the same origin as the Thracians. (See Indo-European Languages.) The country was divided into two parts. (1) Illyris Barbra or Romna, the Roman province of Illyrcum, extended along the Adriatic sea from Italy (Istria), from which it was separated by the Arsia, to the river Drilo, and was bounded on the east by Macedonia and Moesia Superior, from which it was separated by the Drinus, and on the north by Pannonia, from which it was separated by the Dravus. It thus comprehended a part of the modern Croatia, the whole of Dalmatia, almost the whole of Bosnia, and a part of Albania. It was divided in ancient times into three districts, according to the tribes by which it was inhabitedIapydia, the interior of the country on the north, from the Arsia to the Tedanius; Liburnia, along the coast from the Arsia to the Titius; and Dalmatia, south of Liburnia, along the coast from the Titius to the Drilo. The Liburnians submitted at an early time to the Romans; but it was not till after the conquest of the Dalmatians, in the reign of Augustus, that the entire country was organized as a Roman province. From this time the Illyrians, and especially the Dalmatians, formed an important part of the Roman legion.
(2) Illris Graeca, or Illyria Propria, also called Eprus Nova, extended from the Drilo, along the Adriatic, to the Ceraunian Mountains, which separated it from Epirus proper; it was bounded on the east by Macedonia. It thus embraced the greater part of the modern Albania. [p. 870]
It was a mountainous country, but possessed some fertile land on the coast. Its principal rivers were the Aos, Apsus, Genusus, and Panyasus. In the interior was an important lake, the Lychnitis. On the coast there were the Greek colonies of Epidamnus, afterwards Dyrrhachium, and Apollonia. It was at these places that the celebrated Via Egnatia commenced, which ran through Macedonia to Byzantium. The country was inhabited by various tribesAtintanes, Taulantii, Parthini, Dassaretae, etc. In early times they were troublesome and dangerous neighbours to the Macedonian kings. They were subdued by Philip, the father of Alexander the Great, who defeated and slew in battle their king, Bardylis, in B.C. 359. After the death of Alexander the Great, most of the Illyrian tribes recovered their independence. At a later time the injury which the Roman trade suffered from their piracies brought against them the arms of the Republic. The forces of their queen, Teuta, were easily defeated by the Romans, and she was obliged to purchase peace by the surrender of part of her dominions and the payment of an annual tribute (B.C. 229). The second Illyrian war was finished by the Romans with the same ease. It was commenced by Demetrius of Pharos, who was guardian of Pineus, the son of Agron, but he was conquered by the consul Aemilius Paulus in 219. Pineus was succeeded by Pleuratus, who cultivated friendly relations with the Romans. His son Gentius formed an alliance with Perseus, king of Macedonia, against Rome; but he was conquered by the praetor L. Anicius, in the same year as Perseus (168); whereupon Illyria, as well as Macedonia, became subject to Rome. See Bahr, Illyrien (Leipzig, 1876).
In the new division of the Empire under Constantine, Illyricum formed one of the great provinces. It was divided into Illyricum Occidental, which included Illyricum Propria, Pannonia, and Noricum, and Illyricum Oriental, which comprehended Dacia, Moesia, Macedonia, and Thrace.