Strymon: river in Thrace. Today, it is called Struma (in Bulgarian) and Strymonas (in Greek). The poetic name Kara Su, "the black waters", is Turkish.
For the greatest part of its course, it flows more or less directly to the south, accepting the waters of several tribituaries, which make the river navigable. In Antiquity, the river first emptied itself in Lake Prasias, a large expanse of water that has in the twentieth century been converted into a fertile plain, stretching from the northwest to the southeast. Turning south again, the river broke through a range of high and steep hills (the site of a city called Amphipolis), and finally emptied itself, for the second time, in the Aegean Sea near Eïon. The total length of the river is about 415 km.The Athenian historian Thucydides implies that the river was the boundary between the Paeonians (who lived to the west of the river) and the Thracians.note[Thucydides, Peloponnesian War 2.96.3.] When the Paeonians were subdued by the Macedonians, the river became the frontier between Thrace and Macedonia.note[Cf. Strabo, Geography 7, fr.11.]
Several Thracian and Paeonian tribes used to live on the banks of the river. Our sources mention the Agrianians on the upper-Strymon, the Maedians (probably in the southwest of modern Bulgaria), and the Sintians and Bisaltians along the lower reaches of the river. It is difficult to identify the precise area where these people lived, because tribal structures are by nature fluid, and names vary over the ages. Other names referred to are the Laeaeans and Odomantes.
Herodotus tells a famous story about the Achaemenid ruler Xerxes and the river Strymon. When the great king arrived at Nine Roads (an old name for Amphipolis), he decided to sacrifice nine boys and girls to the gods of the Underworld, in order to obtain a save passage across the river.note[Herodotus, Histories 7.114.] The truth of this story has been challenged because human sacrifice is not known as an Iranian cult practice.
Finally, it may be noted that the Strymon was considered to be the winter home of the cranes that migrate to the Nile.note[Claudian, War against Gildo, 475-476.]