Illyrians

The Illyrians (Ancient Greek: Ἰλλυριοί, Illyrioi; Latin: Illyrii or Illyri) were a group of Indo-European tribes in antiquity, who inhabited part of the western Balkans and the south-eastern coasts of the Italian peninsula (Messapia). The territory the Illyrians inhabited came to be known as Illyria to Greek and Roman authors, who identified a territory that corresponds to Croatia, Bosnia and Herzegovina, Slovenia, Montenegro, part of Serbia and most of Albania, between the Adriatic Sea in the west, the Drava river in the north, the Morava river in the east and the mouth of the Aoos river in the south. The first account of Illyrian peoples comes from the Periplus of Pseudo-Scylax, an ancient Greek text of the middle of the 4th century BC that describes coastal passages in the Mediterranean.

These tribes, or at least a number of tribes considered "Illyrians proper", of which only small fragments are attested enough to classify as branches of Indo-European; were probably extinct by the 2nd century AD.

The name "Illyrians", as applied by the ancient Greeks to their northern neighbors, may have referred to a broad, ill-defined group of peoples, and it is today unclear to what extent they were linguistically and culturally homogeneous. In fact, an Illyric origin was and still is attributed also to a few ancient peoples in Italy, in particular the Iapyges, Dauni and Messapi, as it is thought that, most likely, they had followed Adriatic shorelines to the peninsula, coming from the geographic "Illyria". The Illyrian tribes never collectively regarded themselves as 'Illyrians', and it is unlikely that they used any collective nomenclature for themselves. In fact, the name Illyrians seems to be the name applied to a specific Illyrian tribe, which was the first to come in contact with the ancient Greeks during the Bronze Age, causing the name Illyrians to be applied to all people of similar language and customs.

...
Wikipedia