When and why did Ezra go back to Jerusalem?
Ezra went back to Jerusalem around 526 B.C., by the decree of Cyrus, to rebuild the temple that Nebuchadnezzar's forces had utterly destroyed. This return came after the 70-year Babylonian captivity that began when Nebuchadnezzar took the Jews captive to Babylon in 606 B.C.
Les teaches that the time frame follows the Babylonian captivity. Nebuchadnezzar came in 606 B.C. and took Daniel and all the Jews captive back to Babylon. Jeremiah had prophesied that the nation of Israel would go into captivity for 70 years, which brings the return to about 526 B.C. At that time, Ezra went back by the decree of Cyrus to rebuild the temple, which Nebuchadnezzar's forces had utterly destroyed.