Sixty-seven years after the taking of Nineveh by the Aryans, which left Babylonia to the Semitic Chaldeans, the last monarch of the Chaldean Empire (the Second Babylonian Empire), Nabonidus, the father of Belshazzar, was overthrown by Cyrus, the Persian. This Nabonidus, again, was a highly educated monarch, who brought far too much intelligence and imagination and not enough of the short range wisdom of this world to affairs of state. He conducted antiquarian researches, and to his researches it is that we owe the date of 3750 B.C., assigned to Sargon I and still accepted by many authorities. He was proud of this determination, and left inscriptions to record it. It is clear he was a religious innovator; he built and rearranged temples and attempted to centralize religion in Babylon by bringing a number of local gods to the temple of Bel-Marduk. No doubt he realized the weakness and disunion of his empire due to these conflicting cults, and had some conception of unification in his mind. Events were marching too rapidly for any such development. His innovation had manifestly raised the suspicion and hostility of the priesthood of Bel. They sided with the Persians. “The soldiers of Cyrus entered Babylon without fighting.” Nabonidus was taken prisoner, and Persian sentinels were set at the gates of the temple of Bel, “where the services continued without intermission.” Cyrus did, in fact, set up the Persian Empire in Babylon with the blessing of Bel-Marduk. He gratified the conservative instincts of the priests by packing off the local gods back to their ancestral temples. He also restored the Jews to Jerusalem.[142] These were merely matters of immediate policy to him. But in bringing in the irreligious Aryans, the ancient priesthood was paying too highly for the continuation of its temple services. It would have been wiser to have dealt with the innovations of Nabonidus, that earnest heretic, to have listened to his ideas, and to have met the needs of a changing world. Cyrus entered Babylon 539 B.C.; by 521 B.C. Babylon was in insurrection again, and in 520 B.C. another Persian monarch, Darius, was pulling down her walls. Within two hundred years the life had altogether gone out of those venerable rituals of Bel-Marduk, and the temple of Bel-Marduk was being used by builders as a quarry. [Illustration: CHEPHREN] § 7[143]