Ionia, known in Old Persian as Yauna (), was a region within the satrapy of Lydia, with its capital at Sardis, within the First Persian Empire. The first mention of the Yauna is at the Behistun inscription.[note 1]
In the mid-6th century BC, the Ionians were conquered by Cyrus the Great and according to Herodotus, they were placed in the same tax district (the first) as the Pamphylians, Lycians, Magnesians, Aeolians, Milyans, and Carians. It is unclear to what extent the Yauna were advantaged or disadvantaged by Persian rule, and what caused the Ionian Revolt which broke out in c. 499 BC and lasted until 494 BC. The main source, Herodotus, puts it down to the personal ambitions of two men of Miletus, Histiaeus and Aristagoras; modern scholars debate what the underlying reasons may have been; arguments for economic and political causes are variously put forward, but there are no clear sources which can give a definitive answer.
After the revolt was put down, the Ionian cities were subdued by some pragmatic and enlightened measures by the Persian satrap of Sardis, Artaphrenes. The Ionians are reported to have served with the Persian forces which were defeated at Marathon by the Athenians and Plataeans in 490, while they also fought on the Persian side during Xerxes' great Second Persian invasion of Greece of 480-479.
It was only after the Persians were defeated at Battle of Plataea in 479 that the Ionian cities had the confidence to revolt again, defeating the Persian forces at the Battle of Mycale in the same year.
After the Peloponnesian War and the destruction of Athenian power, Sparta ceded Ionia back to Persia in the 387 BCE with the Peace of Antalcidas. Ionia remained under Persian rule until the campaigns of Alexander the Great in 334 BC.
Beside to Yaunas of the plain and sea, there are also mentioned Yauna paradraya (Ionians beyond or across the sea such as Naxos, Thasos and Byzantium) as well the Yauna takabara (Greeks with sunhats, the Macedonians) in Skudra satrapy.
1st Achaemenid period:
2nd Achaemenid period: