The Achaemenid Empire, established by Cyrus the Great in the 6th century B.C., was the first Persian Empire and one of the largest empires of the ancient world. Under Cyrus's leadership, it expanded through successful military campaigns, encompassing regions such as modern-day Iran, parts of the Mediterranean, and even stretching into India. The empire is notable for its administrative innovations, cultural tolerance, and the establishment of a postal system. Cyrus’s respect for the traditions and religions of conquered peoples set a precedent for future empires, demonstrating the importance of governance that embraced diversity and established a relatively peaceful coexistence among different cultures.