The downfall of Lydia prepared the way for a Persian attack on Babylonia. The conquest of that country proved unexpectedly easy. In 539 B.C. the great city of Babylon opened its gates to the Persian host. Shortly afterwards Cyrus issued a decree allowing the Jewish exiles there to return to Jerusalem and rebuild the Temple, which Nebuchadnezzar had destroyed. With the surrender of Babylon the last Semitic empire in the East came to an end. The Medes and Persians, an Indo-European people, henceforth ruled over a wider realm than ever before had been formed in Oriental lands. CAMBYSES, 529-522 B.C. Cyrus was followed by his son, Cambyses, a cruel but stronghanded despot. Cambyses determined to add Egypt to the Persian dominions. His land army was supported by a powerful fleet, to which the Phoenicians and the Greeks of Cyprus contributed ships. A single battle sufficed to overthrow the Egyptian power and to bring the long rule of the Pharaohs to a close. [12] DARIUS THE GREAT, 521-485 B.C. The reign of Darius, the successor of Cambyses, was marked by further extensions of the frontiers. An expedition to the distant East added to the empire the region of the Punjab, [13] along the upper waters of the Indus. Another expedition against the wild Scythian tribes along the Danube led to conquests in Europe and brought the Persian dominions close to those of the Greeks. Not without reason could Darius describe himself in an inscription which still survives, as "the great king, king of kings, king of countries, king of all men." [Illustration: DARIUS WITH HIS ATTENDANTS Bas-relief at Persepolis. The monarch's right hand grasps a staff or scepter, his left hand, a bunch of flowers. His head is surmounted by a crown, his body is enveloped in the long Median mantle. Above the king is a representation of the divinity which guarded and guided him. In the rear are two Persian nobles, one carrying the royal fan, the other the royal parasol.] [Illustration: ROCK SEPULCHERS OF THE PERSIAN KINGS The tombs are those of Darius, Xerxes, and two of their successors. They are near Persepolis.] ORGANIZATION OF THE PERSIAN EMPIRE It was the work of Darius to provide for his dominions a stable government which should preserve what the sword had won. The problem was difficult. The empire was a collection of many peoples widely different in race, language, customs, and religion. Darius did not attempt to weld the conquered nations into unity. As long as the subjects of Persia paid tribute and furnished troops for the royal army, they were allowed to conduct their own affairs with little interference from the Great King. THE SATRAPAL SYSTEM