Cyrus II of Persia, commonly known as Cyrus the Great, was the founder of the Achaemenid Persian Empire. Hailing from Persis, he brought the Achaemenid dynasty to power by defeating the Median Empire and embracing all of the previous civilized states of the ancient Near East, expanding vastly and eventually conquering most of West Asia and much of Central Asia to create what would soon become the largest polity in human history at the time. The Achaemenid Empire's largest territorial extent was achieved under Darius the Great, whose rule stretched from the Balkans and the rest of Southeast Europe in the west to the Indus Valley in the east.

Darius I, commonly known as Darius the Great, was a Persian ruler who served as the third King of Kings of the Achaemenid Empire, reigning from 522 BCE until his death in 486 BCE. He ruled the empire at its territorial peak, when it included much of Western Asia, parts of the Balkans and the Caucasus, most of the Black Sea's coastal regions, Central Asia, the Indus Valley in the far east, and portions of North Africa and Northeast Africa including Egypt (Mudrâya), eastern Libya, and coastal Sudan.