In classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC and the death of Cleopatra VII, followed by the emergence of the Roman Empire, as signified by the Battle of Actium in 31 BC and the conquest of Ptolemaic Egypt the following year. The Ancient Greek word Hellas was gradually recognized as the name for Greece, from which the word Hellenistic was derived. "Hellenistic" is distinguished from "Hellenic" in that the latter refers to Greece itself, while the former encompasses all ancient territories under Greek influence, in particular the East after the conquests of Alexander the Great.

The Achaemenid Empire or Achaemenian Empire, also known as the First Persian Empire, was the ancient Iranian empire founded by Cyrus the Great of the Achaemenid dynasty in 550 BC. Based in modern-day Iran, it was the largest empire by that point in history, spanning a total of 5.5 million square kilometres. The empire spanned from the Balkans and Egypt in the west, West Asia as the base, the majority of Central Asia to the northeast, and the Indus Valley to the southeast.