Lars **** The Bible follows Josephus in introducing a 70-year period from the last deportation to the 1st of Cyrus. This is confirmed by Zechariah 1 and 7 where we find in year 2 of Darius the Mede that the Jews are still in exile 70 years after the fall of Babylon. Zechariah 7 confirms the Jews are still in exile as well in year four of Darius the Mede.****
I believe you are confusing Darius the Mede with Darius the Great as follows:
DARIUS THE GREAT (522-486 B.C.)
Darius made a decree that the work of the temple should be continued without any hindrance (Ezra chapter 6). It was during his reign that the temple was completed (Ezra chapter 6).
Note: Don’t confuse this king with Darius the Mede who is mentioned in the book of Daniel (see Daniel 5:31; 6:1). Darius the Mede was the governor of Babylon under Cyrus the Great.
See list of Persian Kings below .....
THE KINGS OF PERSIA
As you read the books of Ezra, Nehemiah and Esther, you will come across the names of different kings. These men were Persian kings. When you read the names of these kings you can look on this list which will help you to understand who the king was and when he lived.
1. CYRUS THE GREAT (550-530 B.C.)
This is the king that Isaiah had long ago promised would come and deliver the children of Israel (Isaiah 44:28; 45:1-5). He conquered the Babylonians and then allowed the Jews to return to their homeland and to rebuild their temple (Ezra chapter 1). Daniel was still alive when Cyrus was king (Daniel 1:21; 10:1).
2. CAMBYSES (530-522 B.C.)
3. SMERDIS (He ruled less than a year.)
4. DARIUS THE GREAT (522-486 B.C.)
Darius made a decree that the work of the temple should be continued without any hindrance (Ezra chapter 6). It was during his reign that the temple was completed (Ezra chapter 6).
Note: Don’t confuse this king with Darius the Mede who is mentioned in the book of Daniel (see Daniel 5:31; 6:1). Darius the Mede was the governor of Babylon under Cyrus the Great.
5. AHASUERUS or XERXES (486-464 B.C.)
This is the king that we read about in the book of Esther. Esther became his queen. He is also mentioned in Ezra 4:6.
6. ARTAXERXES I (464-423 B.C.)
At first this king sent a decree ordering the Jews to stop rebuilding the city and the walls (see Ezra 4:6-23). Later, however, he allowed his cupbearer, Nehemiah, to return to Jerusalem to rebuild the city walls (Nehemiah chapters 1-2). This is also the same king who had earlier allowed Ezra to return (Ezra chapters 7-8).
These were all great kings, but as we read the books of Ezra, Nehemiah and Esther, we learn that there is a much greater King in heaven who is in control of all things!