In 445 b.c. the Persian King Artaxerxes sent Nehemiah, an Israelite who was a trusted official, to help rebuild the walls of Jerusalem. With Nehemiah went the third wave of returning Jewish exiles. There was intense opposition from the other peoples in the land and disunity within Jerusalem. Despite this opposition, Nehemiah rebuilt the walls. He overcame these threats by taking wise defensive measures, by personal example, and by his obvious courage. Nehemiah did what God had put into his heart (2:12; 7:5) and found that the joy of the Lord was his strength (8:10). When the people began once again to fall into sin, Nehemiah had Ezra read to them from the Law. Nehemiah served twice as governor. The author is unknown, although parts come from Nehemiah's own writings.