The first Achaemenid military incursion in southeast Europe started in 513 BCE, when the Achaemenid king
Darius I amassed an army and marched from Achaemenid-ruled Anatolia into Thrace, and from there he crossed the
Arteskos river and then proceeded through the valley-route of the
Hebros river. This was an act of conquest by Darius I, who during his march sent emissaries to the
Thracians found on the path of his army as well as to the many other Thracian tribes over a wide area. All these peoples of Thrace, including the Odrysae, submitted to the Achaemenid king until his army reached the territory of Thracian tribe of the
Getae who lived just south of the Danube river and who in vain attempted to resist the Achaemenid conquest. After the resistance of the Getae was defeated and they were forced to provide the Achaemenid army with soldiers, all the Thracian tribes between the
Aegean Sea and the
Danube river had been subjected by the Achaemenid Empire. Once Darius had reached the Danube, he crossed the river and
campaigned against the Scythians, after which he returned back to Anatolia through Thrace and left a large army in Europe under the command of his general
Megabazus. Following Darius I's orders to create a new satrapy for the Achaemenid Empire in the Balkans, Megabazus forced the Greek cities who had refused to submit to the Achaemenid Empire, starting with
Perinthus, after which led military campaigns throughout Thrace to impose Achaemenid rule over every city and tribe in the area. With the help of Thracian guides, Megabazus was able to conquer
Paeonia up to but not including the area of Lake Prasias, and he gave the lands of the
Paeonians inhabiting these regions up to the Lake Prasias to Thracians loyal to the Achaemenid Empire. The last endeavours of Megabazus included the conquest of the area between the
Strymon and
Axius rivers, and at the end of his campaign, the king of
Macedonia,
Amyntas I, accepted to become a vassal of the Achaemenid Empire. Within the satrapy itself, the Achaemenid king Darius granted to the tyrant
Histiaeus of
Miletus the district of
Myrcinus on the Strymon's east bank until Megabazus persuaded him to recall Histiaeus after he returned to Asia Minor, after which the Thracian tribe of the
Edoni retook control of Myrcinus. Once Megabazus had returned to Asia Minor, he was succeeded in by a governor whose name is unknown, and Darius appointed the general
Otanes to oversee the administrative division of the Hellespont, which extended on both sides of the sea and included the
Bosporus, the
Propontis, and the
Hellespont proper and its approaches. Otanes then proceeded to capture
Byzantium,
Chalcedon,
Antandrus,
Lamponeia,
Imbros, and
Lemnos for the Achaemenid Empire. The area included within the satrapy of included both the Aegean coast of Thrace, as well as its Pontic coast till the Danube. In the interior, the Western border of the satrapy consisted of the
Axius river and the
Belasica-
Pirin-
Rila mountain ranges till the site of modern-day
Kostenets. The importance of this satrapy rested in that it contained the
Hebros river, where a route in the river valley connected the permanent Persian settlement of
Doriscus with the Aegean coast, as well as with the port-cities of
Apollonia,
Mesembria and
Odessos on the Black Sea, and with the
central Thracian plain, which gave this region an important strategic value. Persian sources describe the province as being populated by three groups: the
Saka Paradraya ("Saka beyond the sea", the Persian term for all
Scythian peoples to the north of the
Caspian and
Black Seas); the themselves (most likely the
Thracian tribes), and
Yauna Takabara. The latter term, which translates as "
Ionians with shield-like hats", is believed to refer to
Macedonians. The three ethnicities (Saka, Macedonian, Thracian) enrolled in the
Achaemenid army, as shown in the Imperial tomb reliefs of
Naqsh-e Rostam, and participated in the
Second Persian invasion of Greece on the Achaemenid side. When Achaemenid control over its European possessions collapsed once the
Ionian Revolt started, the Thracians did not help the Greek rebels, and they instead saw Achaemenid rule as more favourable because the latter had treated the Thracians with favour and even given them more land, and also because they realised that Achaemenid rule was a bulwark against Greek expansion and Scythian attacks. During the revolt, Aristagoras of Miletus captured Myrcinus from the Edones and died trying to attack another Thracian city. Once the Ionian Revolt had been fully quelled, the Achaemenid general
Mardonius crossed the Hellespont with a large fleet and army, re-subjugated Thrace without any effort and made Macedonia full part of the satrapy of . Mardonius was however attacked at night by the
Bryges in the area of
Lake Doiran and modern-day
Valandovo, but he was able to defeat and submit them as well. Herodotus's list of tribes who provided the Achaemenid army with soldiers included Thracians from both the coast and from the central Thracian plain, attesting that Mardonius's campaign had reconquered all the Thracian areas which were under Achaemenid rule before the Ionian Revolt. When the Greeks
defeated a
second invasion attempt by the Persian Empire in 479 BCE, they started attacking the satrapy of , which was resisted by both the Thracians and the Persian forces. The Thracians kept on sending supplies to the governor of Eion when the Greeks besieged it. When the city fell to the Greeks in 475 BCE,
Cimon gave its land to
Athens for colonisation. Although Athens was now in control of the Aegean Sea and the Hellespont following the defeat of the Persian invasion, the Persians were still able to control the southern coast of Thrace from a base in central Thrace and with the support of the Thracians. Thanks to the Thracians co-operating with the Persians by sending supplies and military reinforcements down the Hebrus river route, Achaemenid authority in central Thrace lasted until around 465 BCE, and the governor
Mascames managed to resist many Greek attacks in Doriscus until then. Around this time,
Teres I, the king of the Odrysae tribe, in whose territory the Hebrus flowed, was starting to organise the rise of his kingdom into a powerful state. With the end of Achaemenid power in the Balkans, the Thracian
Odrysian kingdom, the
kingdom of Macedonia, and the
Athenian thalassocracy filled the ensuing power vacuum and formed their own spheres of influence in the area. ==See also==