4th and 3rd century BC

Celtic expansion reached the Carpathians in the beginning of the 4th century BC.^[19] According to Livy, perhaps based on Celtic legend, the Celts that migrated to Italy and Illyria numbered 300,000.^[19] The Celts established themselves in Pannonia, subjugating the Pannonians, and in the end of the 4th century they renewed raids into the Balkans.^[19] By the early 3rd century BC, Pannonia had been Celtiziced.^[20] The Celts, retreating from Delphi (280–278 BC), settled on the mouth of the Sava and called themselves Scordisci.^[20] The Scordisci established control to the north of the Dardani.^[21] There is no mention of the Scordisci until the reign of Philip V of Macedon (r. 221–179 BC), when they emerge as Macedon allies against the Dardani and Rome.^[21] The Scordisci, having conquered the important Sava valley, the only route to Italy, in the second half of the 3rd century BC, "gradually became the most important power in the northern Balkans".^[22]

They controlled the various Pannonian groups in the region, extracting tribute and enjoying the status of the most powerful group in the central Balkans (see the Triballi, Autariatae, Dardanians and Moesians), and they erected fortresses in Singidunum^[23] (today's city of Belgrade) and Taurunum (modern Zemun). They subjugated a number of groups^[when?] in Moesia, including the Dardani, several west Thracian tribes and the Paeonians.^{[citation needed]}

2nd century BC

The Scordisci most likely subdued the Dardani in the mid-2nd century BC, after which there was for a long time no mention of the Dardani.^[24] From 141 BC, the Scordisci were constantly involved in battles against Roman-held Macedonia. They were defeated in 135 BC.^[25][26] by Cosconius in Thrace.^[27] In 118 BC, according to a memorial^[28] stone discovered near Thessalonica, Sextus Pompeius, probably the grandfather of the triumvir, was slain fighting against them near Stobi. In 114 BC, they surprised and destroyed the army of Gaius Porcius Cato^[29] in the western mountains of Serbia, but two years later they were defeated by Marcus Livius Drusus (112 BC) and a few years later again by Minucius Rufus (107 BC).^[30] However, they did not give up their claim over Pannonia, since there is mention of their involvement in the second siege of Sisak in 119 BC.

1st century BC

They still, from time to time, gave trouble to the Roman governors of Macedonia, whose territory they invaded in combination with the Maedi and Dardani. They even advanced as far as Delphi and plundered the temple; but Lucius Cornelius Scipio Asiaticus finally overcame them in 88 BC and drove them across the Danube. After this, the power of the Scordisci declined rapidly. This decline was more a result of the political situation in barbaricum rather than the effects of Roman campaigns, as their clients, especially the Pannonians, became more powerful and politically independent. Between 56 and 50 BC, the Scordisci were defeated by Burebista's Dacians, and became subject to him.^[31]

They were crushed in 15 BC by Tiberius,^[32] and became Roman subjects, playing the part as mercenaries.^[33] Other sources say the Romans made alliance with the Scordisci in Sirmium and Danube valleys following the Alpine campaign under Tiberius in 15 BC, the alliance would be crucial for the victory over the Pannonians (15 BC) and later Breuci (12 BC).

Dacian Conquest

The Dacian conquest of the Scordisci around 50 BC, likely involved a combination of military campaigns, negotiations, and possibly the establishment of a vassal relationship. While specific details are scarce, it's believed that Burebista, the Dacian king, exerted his influence over the Scordisci either through military victories or diplomatic agreements, expanding Dacian control over their territory. The exact nature of this conquest may vary based on historical interpretation and the available evidence.

1st century AD

Strabo's Geographica (20 BC–23 AD) mentions that one subgroup of the Scordisci, the Major Scordisci, lived between the mouth of the Sava and mouth of the Morava,^[34] while the other subgroup, the Minor Scordisci, lived to the east of the Morava, bordering the Moesi and Triballi.

They started receiving Roman citizenship during Trajan's rule (98–117 AD).^[35] With their Romanization, they ceased to exist as an independent ethno-political unit.^[36]