Imperial Expansion under Darius
Early victories
Samos was the first new territory to be brought into the empire in 517
By 513, Lesbos and Chios were also incorporated - important because they were on a significant grain route and so had a strategic position
A Greek named Scylax was sent by Darius to explore the Indus Valley, and to bring them into the empire, which he did
Thrace + Scythia
In 513 Darius led a huge force into Europe in an attempt to conquer Thrace and Western Scythia
His army came to the river Ister and built a bridge across, the Persians then marched into Scythia and left the Ionians behind to guard the bridge
However, the Scythians were a nomadic tribe and so used a tactic where they split up and tried to move around as much as possible
This made it challenging for the Persians to make any real progress in conquering and, after several months, Darius gave up and decided to return to the Ister. Herodotus claims that he left his weakest men behind
The Scythian got to the Ister before the Persians could, and tried to convince the Ionians to cut down the bridge and desert.
The Ionians refused which importantly shows a loyalty to Darius, even if it is just in the interest of personal safety and stability
Darius returns home and orders Megabazus to take Thrace, which he does within the same year of 513
What came next?
Darius then sent requests for Earth and Water to the Macedonians who submitted but weren't fully incorporated into the empire until 492
Lemnos and Imbros were also incorporated into the empire
Overall
Herodotus presents this expedition as a disaster but overall it can be seen as a success:
Thrace had many valuable resources such as gold, silver and timber to build ships
Persians could now control sea routes from the Aegean to the Black Sea
Why?
Subdue the Scythian tribes which had made continual raids into his territory
Establish a foothold for further expansion into Europe.
Access to the minerals, metals and forest deposits