Cyrus II of Persia, commonly known as Cyrus the Great, and also Cyrus the Elder by the Greeks, was founder of the Achaemenid Empire, the first Persian Empire. Under his rule, the empire embraced all the previous civilized states of the ancient near east, expanded vastly and eventually conquered most of Western Asia and much of Central Asia.

From the Mediterranean sea and Hellespont in the west to the Indus River in the east, Cyrus the Great created the largest empire the world had yet seen. Under his successors, the empire eventually stretched at its maximum extent from parts of the Balkans and South-east Europe proper in the west, to the Indus Valley in the east.

The reign of Cyrus the Great lasted about 30 years and he built his empire by first conquering the Median Empire, then the Lydian Empire, and eventually the Neo-Babylonian Empire. He led an expedition into Central Asia, which resulted in major campaigns that were described as having brought "into subjection every nation without exception". Cyrus did not venture into Egypt, and was alleged to have died in battle fighting the Massagetae along the Syr Darya in December 530 BC. However, Xenophon stated that Cyrus did not die in battle and returned to the capital again.

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