Jeremiah the prophet identified a period of 70 years during which the Jews would be kept in captivity, away from their land and their heritage (25:11-12, 29:10). The return Jeremiah promised was accomplished on time. But it required a change in world leadership, which God brought about at his intended time.
The Persian Empire. Babylon had replaced Assyria as dominant world power – a feat accomplished under brilliant military leadership. Babylon itself fell to another brilliant conqueror, Cyrus the Great. The rise of Cyrus was spectacular. Coming from a minor district in the east, Cyrus took the province of Persia. Bu 550 B.C. he had added the larger Media. He then crushed King Croesus and added Lydia to his territories. The city surrendered without a fight, and welcomed Cyrus as a deliverer. Now Cyrus simply placed himself and his officials atop the Babylonian administrative system, and then controlled more land than anyone before him. From the Aegean Sea to India, the east was his.
The Medo-Persians retained control of the empire all during the extended time of the Jewish return to their land.
Cambyses (530-522) succeeded his father Cyrus, and added Egypt to the empire. Darius Hytaspes (522-486) was the next ruler. He was a military commander, but showed much skill in reorganizing the empire. He attempted to move into Europe, but was thrown back by the Greeks at the battle of Marathon in 490 B.C. Darius was seceded by Xerxes. He invaded Greece and burned Athens, but he too was at last thrown back. This Xerxes, called Ahasuerus in the Bible, is the person who makes the Jewish girl Esther his queen.
The final Persian ruler of this period who overlaps the Bible record is Artaxerxes (465-425).
The OT books that tell the story of the return fit into this extended period of time during which the Persian empire has replaced Babylonian, and prior to its own fall before a victorious Alexander the Great of Macedon.
Dates of the return. The deportation to Babylon came in stages with different groups of Jews taken there in 605, 
597, and 586 B.C. The return also took place in stages. A pioneer group headed home in 538 B.C., a 2nd group came some 8 years later in 458, and final group in 444 B.C.
The return was possible because Cyrus revered the policy of the Assyrians and Babylonians, and encouraged ethnic groups to go back to their homelands. In the first year of his rule in Babylon, Cyrus, possibly influenced by Daniel, issued the edict that freed the Jews to return. The edict ordered them to rebuild the temple at Jerusalem, and ordered that all costs be paid from the Persian treasury! In addition, all the gold and silver vessels used in worship were released as well. Thus it is likely that the first group of 42,360 pilgrims turned toward their homeland in 538 or 537 B.C.
The temple foundations were quickly laid by this group. But opposition from the Samaritans and flagging zeal left the structure incomplete for over a decade. The building was completed then, urged on by the prophets Haggai and Zechariah.
The second return came 58 years after the temple was completed. The leader at this time was Ezra, a Babylonian official who was also a devoted student of the Word of God. Ezra’s great contribution and his mission was to strengthen the people in the land spiritually.
A 3rd return took place under Nehemiah, in 444 B.C. Nehemiah’s mission was to rebuild the walls of the city, and to lead another spiritual reformation. This mission accomplished, Nehemiah spent most of the rest of his life in the land and served as Persian governor of the province in which the Jews lived.
The Book of Malachi concludes the OT record, and reveals conditions in the land some decades after Nehemiah.
