Artabazos I of Phrygia

When Xerxes I was assassinated in 465 BC, he was succeeded by his son Artaxerxes I, but several parts of the Achaemenid empire soon revolted, foremost of which were Bactria and Egypt. The Egyptian Inarus defeated the Persian satrap of Egypt Achaemenes, a brother of Artaxerxes, and took control of Lower Egypt. He contacted the Greeks, who were also officially still at war with Persia, and in 460 BC, Athens sent an expeditionary force of 200 ships and 6000 heavy infantry to support Inarus. The Egyptian and Athenian troops defeated the local Persian troops of Egypt, and captured the city of Memphis, except for the Persian citadel which they besieged for several years.

Megabyzus fought against the Athenians and the Egyptians in the Siege of Memphis (459-455 BC) and the Siege of Prosopitis (455 BC).

Egyptian soldier, circa 470 BC. Xerxes I tomb relief.

The Athenians and Egyptians had settled down to besiege the local Persian troops in Egypt, at the White Castle. The siege evidently did not progress well, and probably lasted for at least four years, since Thucydides says that their whole expedition lasted 6 years,[6] and of this time the final 18 months was occupied with the Siege of Prosoptis.[7]

According to Thucydides, at first Artaxerxes sent Megabazus to try and bribe the Spartans into invading Attica, to draw off the Athenian forces from Egypt. When this failed, he instead assembled a large army under Megabyzus, and dispatched it to Egypt.[7] Diodorus has more or less the same story, with more detail; after the attempt at bribery failed, Artaxerxes put Megabyzus and Artabazus in charge of 300,000 men, with instructions to quell the revolt. They went first from Persia to Cilicia and gathered a fleet of 300 triremes from the Cilicians, Phoenicians and Cypriots, and spent a year training their men. Then they finally headed to Egypt.[8] Modern estimates, however, place the number of Persian troops at the considerably lower figure of 25,000 men given that it would have been highly impractical to deprive the already strained satrapies of any more man power than that.[9] Thucydides does not mention Artabazus, who is reported by Herodotus to have taken part in the second Persian invasion; Diodorus may be mistaken about his presence in this campaign.[10] It is clearly possible that the Persian forces did spend some prolonged time in training, since it took four years for them to respond to the Egyptian victory at Papremis. Although neither author gives many details, it is clear that when Megabyzus finally arrived in Egypt, he was able to quickly lift the Siege of Memphis, defeating the Egyptians in battle, and driving the Athenians from Memphis.[7][11]

The Athenians now fell back to the island of Prosopitis in the Nile delta, where their ships were moored.[7][11] There, Megabyzus laid siege to them for 18 months, until finally he was able to drain the river from around the island by digging canals, thus "joining the island to the mainland".[7] In Thucydides's account the Persians then crossed over to the former island, and captured it.[7] Only a few of the Athenian force, marching through Libya to Cyrene survived to return to Athens.[6] In Diodorus's version, however, the draining of the river prompted the Egyptians (whom Thucydides does not mention) to defect and surrender to the Persians. The Persians, not wanting to sustain heavy casualties in attacking the Athenians, instead allowed them to depart freely to Cyrene, whence they returned to Athens.[11] Since the defeat of the Egyptian expedition caused a genuine panic in Athens, including the relocation of the Delian treasury to Athens, Thucydides's version is probably more likely to be correct.[12]