All Roman troops are withdrawn in 194…

The region of present Salerno in Campania, located about thirty miles (fifty kilometers) southeast of present Naples on a hill overlooking the Gulf of Salerno, has been continuously settled since prehistoric times, although the first certain signs of human presence date to the period between the ninth and sixth centuries BCE.

The Oscan-Etruscan settlement of Irna (founded in the sixth century BCE), situated across the Irno river, in today's Salernitan quarter of Fratte, represented an important base for Etruscan trade with the Greek colonies of Posidonia and Elea.

The Samnites had occupied it around the fifth century BCE as a consequence of the Battle of Cumae (474 BCE) as part of the Syracusan sphere of influence.

With the Roman advance in Campania, Irna began to lose its importance, being supplanted by the new Roman colony (194 BCE) of Salernum, developing around an initial castrum.

Antiochus, as part of the peace treaty with Egypt in 194/193, also gives his daughter Cleopatra in marriage to Ptolemy V.

Egypt practically becomes a Seleucid protectorate.

Antiochus offers an alliance to Philip, whom he had previously forsaken, in 193 BCE but is rebuffed: Philip joins Rome, together with …

…Rhodes, Pergamon, and …

…the Achaean League.

Only the Aetolians, discontent with Rome's growing influence in Greece and still smarting from the frustration of their ambitions by Flamininus, call upon Antiochus to be their liberator and appoint him commander in chief of their league.

Philopœmon, the Achaean League’s general, desires to control Sparta itself, and finds his opportunity in the revolts in the Spartan seaports instigated by Nabis, following the Roman departure from Greece in 194.

Sparta, recovering its ports, besieges Gythium’s Acraean garrison.

Philopœmon, upon securing a promise of support from Flamininus, marches to Gythium in advance of the Romans to open the campaign.

While the Romans bring the operation to its successful completion in 192, Philopœmon’s forces, failing against Nabis by sea, pursue Nabis’ army toward Mount Barbosthenes, where they nearly annihilate the Spartan forces.

Philopœmon installs a blockade of Sparta, then ravages Laconia, but Flamininus halts the fighting and restores equilibrium, thwarting Philopœmon’s plans to annex Sparta.

The Aetolians, as part of their scheme to precipitate war between Rome and Antiochus, eventually murder Nabis in 192 and temporarily occupy Sparta.

Philopoemen soon expels the Aetolians and induces Sparta to join the Achaean confederation with a promise of no interference in its internal affairs.

The Romans have on several occasions sent ambassadors demanding that Antiochus stay out of Europe and set free all the autonomous communities in Asia Minor.

To meet these demands would mean the actual dissolution of the western part of the Seleucid Empire, and Antiochus thus refuses.

When the Romans show little interest in compromise, Antiochus accepts the invitation of Rome's former allies, the Aetolians, who feel they had not been duly rewarded with additional territory after the victory over Philip, to liberate the Greeks.

Relying on the Aetolians, Antiochus lands in Demetrias in the autumn of 192 with only ten thousand five hundred men and occupies Euboea.

When Antiochus refuses to withdraw, …

...Flamininus announces that Rome's next mission is the liberation of the Greek cities of Asia.