The Achaemenid Empire -- The First Persian Empire (550-330 BC)

Alexander of Macedon invades the Persian Empire in 334 BC, defeats Darius III at Issus (333 BC) and Gaugamela (331 BC), and captures Persepolis, which is burned. Darius III is assassinated by his own satraps, and the Achaemenid Empire falls after 220 years. Alexander adopts many Achaemenid administrative practices, demonstrating the empire's lasting institutional legacy.

After the death of Darius II, Persia experiences succession disputes, rebellions (including the revolt of Cyrus the Younger, which Xenophon chronicles in the Anabasis), and the loss of Egypt for decades. The later Achaemenid kings struggle with a weakening central authority, though Artaxerxes III briefly reconquers Egypt in 343 BC.

After decades of intermittent warfare and Athenian-led campaigns in Egypt and Cyprus, Athens and Persia agree to the Peace of Callias. Persia agrees to stay out of the Aegean, and Athens ceases operations in Persian territory. The empire enters a period of relative stability.

Xerxes I, Darius' successor, leads a colossal invasion force across the Hellespont via bridge of boats. The campaign includes the heroic stand of 300 Spartans at Thermopylae, the burning of Athens, and the decisive Greek naval victory at Salamis that turns the tide.

Darius I sends a punitive expedition against Athens for supporting the Ionian Revolt. The Athenian army, heavily outnumbered, achieves a stunning victory at Marathon. The battle becomes a foundational legend of Western civilization and inspires the modern marathon race.

The Ionian Greek cities of western Anatolia, supported by Athens and Eretria, rebel against Persian rule. The revolt is eventually crushed (494 BC), but it triggers the Greco-Persian Wars that would define the next two decades of Aegean history.

Following the death of Cambyses and a period of turmoil, Darius I seizes the throne. He reorganizes the empire into 20 provinces (satrapies), each with a governor (satrap), introduces standardized coinage (the daric), and begins construction of Persepolis. He also builds the Royal Road, a 2,500-kilometer highway from Susa to Sardis.

Cambyses II, son of Cyrus, defeats the Egyptian pharaoh Psamtik III at the Battle of Pelusium and annexes Egypt. The Achaemenid Empire now stretches from the Indus River to the Nile, becoming the largest empire in history to that point.

Cyrus conquers Babylon without a major battle. He issues the Cyrus Cylinder, often called the first human rights charter, which respects local customs and allows deported peoples, including the Jews, to return to their homelands. This policy of religious and cultural tolerance becomes a hallmark of the empire.

Cyrus defeats King Croesus of Lydia, whose name becomes synonymous with wealth, and brings all of Anatolia under Persian control. The conquest opens Persian access to the Aegean Sea and Greek city-states of Ionia.

Cyrus II of Persis leads a successful revolt against the Median Empire, uniting the Persian and Median peoples and founding the Achaemenid dynasty. Within a decade, Cyrus would transform a small vassal kingdom into history's first true superpower.