Question:
Daniel 1:21 says that Daniel remained in the Babylonian court until the first year of Cyrus, which as you say, was 539/8BC, the year Cyrus conquered Babylon and became king of Babylon as attested by Ezra 5:13, as well as king of Persia as attested by Ezra 4:5. When did Darius the son of Ahasuerus (Daniel 9:1) , who is Artaxerxes, who comes after Cyrus and Darius according to Ezra 6:14, when did he become king of Babylon ?