About the same time, at the beginning of this winter, Sitalces, son of Teres, the Odrysian king of Thrace, made an expedition against Perdiccas, son of Alexander, king of Macedonia, and the Chalcidians in the neighbourhood of Thrace; his object being to enforce one promise and fulfil another. 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 neighbourhood 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.
The empire of the Odrysians extended along the seaboard from Abdera to the mouth of the Danube in the Euxine. The navigation of this coast by the shortest route takes a merchantman four days and four nights with a wind astern the whole way: by land an active man, travelling by the shortest road, can get from Abdera to the Danube in eleven days. Such was the length of its coast line. Inland from Byzantium to the Laeaeans and the Strymon, the farthest limit of its extension into the interior, it is a journey of thirteen days for an active man. The tribute from all the barbarian districts and the Hellenic cities, taking what they brought in under Seuthes, the successor of Sitalces, who raised it to its greatest height, amounted to about four hundred talents in gold and silver. There were also presents in gold and silver to a no less amount, besides stuff, plain and embroidered, and other articles, made not only for the king, but also for the Odrysian lords and nobles. For there was here established a custom opposite to that prevailing in the Persian kingdom, namely, of taking rather than giving; more disgrace being attached to not giving when asked than to asking and being refused;and although this prevailed elsewhere in Thrace, it was practised most extensively among the powerful Odrysians, it being impossible to get anything done without a present. It was thus a very powerful kingdom; in revenue and general prosperity surpassing all in Europe between the Ionian Gulf and the Euxine, and in numbers and military resources coming decidedly next to the Scythians, with whom indeed no people in Europe can bear comparison, there not being even in Asia any nation singly a match for them if unanimous, though of course they are not on a level with other races in general intelligence and the arts of civilized life.
It was the master of this empire that now prepared to take the field. When everything was ready, he set out on his march for Macedonia, first through his own dominions, next over the desolate range of Cercine that divides the Sintians and Paeonians, crossing by a road which he had made by felling the timber on a former campaign against the latter people. Passing over these mountains, with the Paeonians on his right and the Sintians and Maedians on the left, he finally arrived at Doberus, in Paeonia, losing none of his army on the march, except perhaps by sickness, but receiving some augmentations, many of the independent Thracians volunteering to join him in the hope of plunder; so that the whole is said to have formed a grand total of a hundred and fifty thousand. Most of this was infantry, though there was about a third cavalry, furnished principally by the Odrysians themselves and next to them by the Getae. The most warlike of the infantry were the independent swordsmen who came down from Rhodope; the rest of the mixed multitude that followed him being chiefly formidable by their numbers.