The Achaemenid Empire was founded by Cyrus the Great around 550 BC. This empire is notable for uniting various tribes and cultures under a single rule, establishing one of the largest empires in history. Cyrus's governance was characterized by his respect for the customs and religions of the conquered peoples, which fostered loyalty and stability within the empire. The Achaemenid Empire expanded significantly under Cyrus and his successors, extending from parts of the Balkans in the west to the Indus Valley in the east. This diverse and innovative civilization contributed to advancements in governance, infrastructure, and trade.