Axial Age
The Axial Age (mid-First Millennium BC) witnessed unprecedented imperial expansion in the Indo-Mediterranean region and China. The successful and extensive Achaemenid Empire (550–330 BC), also known as the first Persian Empire, covered Mesopotamia, Egypt, parts of Greece, Thrace, the Middle East, much of Central Asia, and North-Western India. It is considered the first great empire in history or the first "world empire". It was overthrown and replaced by the short-lived empire of Alexander the Great. His Empire was succeeded by three Empires ruled by the Diadochi—the Seleucid, Ptolemaic, and Macedonian, which, despite being independent, are called the "Hellenistic Empire" by virtue of their similarities in culture and administration.