The Illyrian king, Bardyllis turned Illyria into a formidable local power in the 4th century BC. The main cities of the Illyrian kingdom were Scodra (present-day Shkodra, Albania) and Rhizon (present-day Risan, Montenegro). In 359 BC, King Perdiccas III of Macedon was killed by attacking Illyrians.
But in 358 BC, Philip II of Macedon, father of Alexander the Great, defeated the Illyrians and assumed control of their territory north and west of Lake Ohrid. Alexander himself routed the forces of the Illyrian chieftain Cleitus the Illyrian in 335 BC, and Illyrian tribal leaders and soldiers accompanied Alexander on his conquest of Persia.
After Alexander's death in 323 BC, independent Illyrian kingdoms again arose. In 312 BC, King Glaukias seized Epidamnus. By the end of the 3rd century BC, an Illyrian kingdom based in Scodra (now a city in Albania) controlled parts of northern Albania, Montenegro, and Herzegovina. Under Queen Teuta, Illyrians attacked Roman merchant vessels plying the Adriatic Sea and gave Rome an excuse to invade the Balkans. In the Illyrian Wars of 229 BC and 219 BC, Rome overran the Illyrian settlements in the Neretva river valley and suppressed the piracy that had made the Adriatic unsafe. In 180 BC, the Dalmatians declared themselves independent of the Illyrian king Gentius, who kept his capital at Scodra. The Romans defeated Gentius, the last king of Illyria, at Scodra in 168 BC and captured him, bringing him to Rome in 165 BC. Four client-republics were set up, which were in fact ruled by Rome. Later, the region was directly governed by Rome and organized as a province, with Scodra as its capital
After the province of Illyricum was divided into Dalmatia and Pannonia in 10, the terms "Illyria" and "Illyrian" would generally go out of use, but would still be used in some circles. The name Illyria was revived by Napoleon for the 'Provinces of Illyria' that were incorporated into the French Empire from 1809 to 1813, and the Kingdom of Illyria was part of Austria until 1849, after which time it was not used in the reorganised Austro-Hungarian Empire. The adjective "Illyrian" was also used in political and literary circles during the 19th century Balkan nationalist movements to describe Non-Slavic ideas of unification and independence from Slavs and other foreign powers.
In drama and literature Illyria can be a half-fictional country, e.g., in William Shakespeare's Twelfth Night, Jean-Paul Sartre's Les Mains Sales and in Lloyd Alexander's The Illyrian Adventure ISBN 0-14-130313-1.