Megabazus was a highly regarded Persian general under Darius. Most information about him comes from The Histories

Histories (Herodotus)

The Histories of Herodotus is considered one of the seminal works of history in Western literature. Written from the 450s to the 420s BC in the Ionic dialect of classical Greek, The Histories serves as a record of the ancient traditions, politics, geography, and clashes of various cultures that...

by Herodotus

Herodotus

Herodotus was an ancient Greek historian who was born in Halicarnassus, Caria and lived in the 5th century BC . He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a...

. Troops left behind in Europe after a failed attempt to conquer the Scythians were put under the command of Megabazus. He was given a mission to conquer Thrace

Thrace

Thrace is a historical and geographic area in southeast Europe. As a geographical concept, Thrace designates a region bounded by the Balkan Mountains on the north, Rhodope Mountains and the Aegean Sea on the south, and by the Black Sea and the Sea of Marmara on the east...

, in which he defeated several cities, including Perinthus and Paeonia

Paionia

In ancient geography, Paeonia or Paionia was the land of the Paeonians . The exact original boundaries of Paeonia, like the early history of its inhabitants, are very obscure, but it is believed that they lay in the region of Thrace...

. He then removed the Paeonians from their homeland and brought them to Darius in Sardis

Sardis

Sardis or Sardes was an ancient city at the location of modern Sart in Turkey's Manisa Province...

. Megabazus was suspicious of Histiaeus

Histiaeus

Histiaeus , the son of Lysagoras, was the tyrant of Miletus in the late 6th century BC.Histiaeus owed his status as tyrant of Miletus to Darius I, king of Persia, who had subjugated Miletus and the other Ionian states in Asia Minor....

 and advised Darius to bring him to Susa

Susa

Susa was an ancient city of the Elamite, Persian and Parthian empires of Iran. It is located in the lower Zagros Mountains about east of the Tigris River, between the Karkheh and Dez Rivers....

 to keep a closer eye on him. His suspicions turned out to be true as Histiaeus provoked a revolt in the town he was formally in charge of and later sided with the Greeks against Persia. The successor to Megabazus's command was Otanes.