India's oldest civilization, known as the Indus Valley Civilization or the Harappan Civilization, was contemporary with ancient Mesopotamia and ancient Egypt and had extensive contacts with the former, making it one of the most important early civilizations in the world. Spread out along the rivers of the Indus River Valley, hundreds of settlements began forming around 3300 BCE, eventually coalescing into a society that had all of the hallmarks of a true civilization, including writing, well-developed cities, a complex social structure, and long-distance trade.

During the last centuries of the first millennium BCE, most of the Mediterranean basin and the Near East were either directly or indirectly under the influence of Hellenism. The Greeks spread their ideas to Egypt, Mesopotamia, and Persia and attempted to unify all of the peoples of those regions under one government. Although some of the Hellenistic kingdoms proved to be powerful in their own rights – especially Ptolemaic Egypt and the Seleucid Empire, which encompassed all of Mesopotamia, most of the Levant, and much of Persia during its height – no single kingdom ever proved to be dominant. The Hellenic kingdoms battled each other for supremacy and even attempted to claim new lands, especially to the east, past the Indus River in lands that the Greeks referred to generally as India. But as the Hellenistic Greeks turned their eyes to the riches of India, a dynasty came to power that put most of the Indian subcontinent under the rule of one king. The dynasty that came to power in the late 4th century BCE is known today as the Mauryan Dynasty, and although the ruling family was short-lived and their power was ephemeral, its influence resonated for several subsequent centuries and spread as far east as China and into the Hellenistic west.