The area roughly corresponded to part or all of the territories of today's Albania, Kosovo, Montenegro, Serbia, Bosnia and Herzegovina, Croatia, and Slovenia.

The area roughly corresponded to modern northern Albania, Kosovo, Serbia, Slovenia, Montenegro, Bosnia and Herzegovina and coastal Croatia (Dalmatiae).

With a powerful fleet the Ardiaei had invaded the Greek cities of Epidamnos (modern Durrës, Albania) Pharos (Stari Grad, Croatia), the island of Corfu and attacked Elis and Messenia in the Peloponnese and Phoenice in Epirus, a hub of Roman trade.

[6] In 156 BC the Dalmatae made an attack of the Illyrian subjects of Rome (this source by Appian is considered ambiguous) and refused to see Roman ambassadors.

[7] Livy's Periochae recorded the campaign of Gaius Marcius Figulus and noted that in the next year, 155 BC, the consul Scipio Nasica Corculum subdued the Dalmatae.

In 129 BC the consul Gaius Sempronius Tuditanus and Tiberius Pandusa waged a war with the Iapydes who lived on the Alps (in the north of Illyria), and seemed to have subjugated them.

[9] However, according to Livy, Sempronius Tuditanus was at first unsuccessful, "but the defeat was compensated by a victory won through the qualities of Decimus Junius Brutus (the man who had subdued Lusitania).

[11] In a passage Appian wrote that in 119 BC the consul Lucius Caecilius Metellus Dalmaticus waged war against the Dalmatae even though they had not done anything wrong because he wanted a triumph.

[9] Caecilius Metellus was given the agnomen Dalmanticus, In 115 BC the consul Marcus Aemilius Scaurus, conducted operations in Gallia Cisalpina against the Ligures in the west and against the Carni and Taurisci (two Gallic tribes which lived in today's Slovenia) in the east.

In 59 BC the lex Vatinia assigned to the consul, Julius Caesar, the proconsulship of Gallia Cisalpina (in northern Italy) and Illyricum and the command of three legions based at Aquileia for a period of five years.

In the past Liguria (which often rebelled), Bruttium (today's Calabria, where there was a chance of unrest) and Gallia Cisalpina (in case of rebellions or possible invasions) had been assigned as provinces in this sense.

Burebista had led the Dacians from what is today's Romania to the conquest of the Hungarian Plain west of the River Danube and close to Illyricum and Italy.

[21] Appian wrote that Aulus Gabinius led fifteen cohorts (which would amount to about 7,800 soldiers) and 3,000 cavalry and that, again, being busy with the civil war, Caesar did not pursue the matter further.

However, the soldiers of his three legions (minus the lost cohorts), who disliked him, defected to Brutus, who then went on to engage Gaius Antonius who was in Apollonia (near Fier, Albania).

Velleius Paterculus wrote that just before the Sicilian Revolt Octavian made frequent expeditions in "Illyricum and Dalmatia" in order not to keep his troops idle and to battle-harden them.

[29] In 35 BC Octavian campaigned against the Iapydes who had carried out raids against Aquileia, plundered Tergestus (Trieste) and had destroyed Pola (Pula) in the previous year.

The next day they sent messengers who offered to give fifty hostages and promised to receive a garrison and to assign to the Romans the highest hills while they would occupy the lower ones.

He set out to lead an expedition into Britain and had already reached Gaul in the winter of 34 BC when some of the newly conquered peoples in Pannonia and the Dalmatians rose in revolt.

They had up to 12,000 troops led by Versus, who had seized Promona (south of modern Knin, Croatia) from the Liburnians) and fortified it even though it was a tough mountain stronghold.

[34] Still in 34 BC, the Romans seized the town of Sunodium at the edge of the forest in which the army of Aulus Gabinius had been entrapped by the Dalmatians in a long and deep gorge between two mountains.

[36] Appian also wrote that Octavian overcame the Oxyaei, the Perthoneatae, the Bathiatae, the Taulantii, the Cambaei, the Cinambri, the Meromenni, and the Pyrissaei, the Docleatae, the Carui, the Interphrurini, the Naresii, the Glintidiones, the Taurisci, the Hippasini and the Bessi.

Illyricum became a province as a formal administrative unit in 27 BC, as part of the settlement by which the Roman senate formalised Octavian's personal rule.

[38] The coastal area was subdivided into three regions called conventus juridicus which were named after the towns of Scardona (Skradin), Salona and Narona (near Metković).

Dyrrachium (Durrës, in modern Albania) and Brundisium (Brindisi, in southern Italy) were the ports used to cross the Adriatic Sea for the journeys from Rome to the eastern Mediterranean and vice versa.

There were important Roman communities in a number of towns on the central and southern part of the coast of today's Croatia, such as Iader (Zadar), Salona (Solin, on the outskirts of Split), Narona (near Metković), and Epidaurus (Epidaurum in Latin, modern Cavtat, near Dubrovnik).

Cassius Dio wrote that in that year the governor of Illyria for 17–16 BC, Publius Silius Nerva, went to fight in the Italian Alps because there were no troops there.

The Dentheletae (a Thracian tribe in eastern Moesia), together with the Scordisci (who lived in today's Serbia, at the confluence of the Rivers Savus [Sava], Dravus [Drava] and Danube) attacked the Roman province of Macedonia (Greece).

Bato the Breucian, the military leader of the Breuci, the largest tribe in southern Pannonia, marched on Sirmium (Sremska Mitrovica, in today's Serbia).

[54][55] In 8 AD the Dalmatians and the Pannonians wanted to sue for peace due to famine and disease, but they were prevented from doing so by the rebels, who had no hope of being spared by the Romans and continued to resist.

Justinian I (reigned 527–565) was born in Tauresium, in the province of Dardania in the Diocese of Dacia (20 kilometres [12 miles] southeast of Skopje in today's North Macedonia).