Darius I, by name Darius the Great, was a king of Persia, one of the greatest rulers of the Achaemenid dynasty, who was noted for his administrative genius and for his great building projects. Darius attempted several times to conquer Greece; his fleet was destroyed by a storm, and the Athenians defeated his army at Marathon.
Although Darius consolidated and added to the conquests of his predecessors, it was as an administrator that he made his greatest contribution to Persian history. He completed the organization of the empire into satrapies, initiated by Cyrus the Great, and fixed the annual tribute due from each province. During his reign, ambitious and far-sighted projects were undertaken to promote imperial trade and commerce.
Coinage, weights, and measures were standardized and land and sea routes developed. An expedition led by Scylax of Caryanda sailed down the Indus River and explored the sea route from its mouth to Egypt, and a canal from the Nile River to the Red Sea, probably begun by the chief of the Egyptian delta lords, Necho I, was repaired and completed.
While measures were thus taken to unite the diverse peoples of the empire by a uniform administration, Darius followed the example of Cyrus in respecting native religious institutions. In Egypt, he assumed an Egyptian titulary and gave active support to the cult. He built a temple to the god Amon in the Kharga oasis, endowed the temple at Edfu, and carried out restoration work in other sanctuaries.