Darius the Great: Organizing the EmpireDarius I (Old Persian Dârayavauš): king of ancient Persia, whose reign lasted from 522 to 486. He seized power after killing king Gaumâta, fought a civil war (described in the Behistun inscription), and was finally able to refound the Achaemenid empire, which had been very loosely organized until then. Darius fought several foreign wars, which brought him t..