History of the Peloponnesian War

On the one hand Perdiccas had made him a promise, when hard pressed at the commencement of the war, upon condition that Sitalces should reconcile the Athenians to him and not attempt to restore his brother and enemy, the pretender Philip, but had not offered to fulfil his engagement; on the other he, Sitalces, on entering into alliance with the Athenians, had agreed to put an end to the Chalcidian war in Thrace.

These were the two objects of his invasion. With him he brought Amyntas, the son of Philip, whom he destined for the throne of Macedonia, and some Athenian envoys then at his court on this business, and Hagnon as general; for the Athenians were to join him against the Chalcidians with a fleet and as many soldiers as they could get together.

Beginning with the Odrysians, he first called out the Thracian tribes subject to him between Mounts Haemus and Rhodope and the Euxine and Hellespont; next the Getae beyond Haemus, and the other hordes settled south of the Danube in the neighborhood of the Euxine, who, like the Getae, border on the Scythians and are armed in the same manner, being all mounted archers.

Besides these he summoned many of the Hill Thracian independent swordsmen, called Dii and mostly inhabiting Mount Rhodope, some of whom came as mercenaries, others as volunteers;

also the Agrianes and Laeaeans, and the rest of the Paeonian tribes in his empire, at the confines of which these lay, extending up to the Laeaean Paeonians and the river Strymon, which flows from Mount Scombrus through the country of the Agrianes and Laeaeans; there the empire of Sitalces ends and the territory of the independent Paeonians begins.

Bordering on the Triballi, also independent, were the Treres and Tilataeans, who dwell to the north of Mount Scombrus and extend towards the setting sun as far as the river Oskius. This river rises in the same mountains as the Nestus and Hebrus, a wild and extensive range connected with Rhodope.