It was not until the reign of his successor Darius I (522-486 B.C.) that the rebuilding of the Temple in Jerusalem was finally taken in hand. Almost twenty years had passed since the foundations had been laid. At the request of the official responsible for the administration of Judah, the Satrap of Transeuphrates, Darius I expressly confirmed the permit issued by Cyrus. The official exchange of letters with the Persian court on this matter can be found in the Book of Ezra (5-6, 6-12).
Many experts are convinced of the historicity of these documents although others are doubtful. If they are not genuine, however, they are very clever imitations both as to form and content. The Bible here even uses the Aramaic of the empire, the commercial language of the Achaemenide Empire. Numerous other contemporary texts confirm, moreover, the extent to which Darius fostered the indigenous cults of the peoples incorporated in his empire, not only in Palestine, but also in Asia Minor and Egypt.
For example the inscription of Usahor, an Egyptian doctor, runs as follows- “King Darius — may he live for ever — commanded me to go to Egypt… and make up once more the number of the holy scribes of the temple and bring new life into what had fallen into decay….”
Werner Keller. The Bible as History. Bantam Books. New York. 1982. p.332-333.