Cyrus was a King of Persia, founder of the Achaemenian dynasty and the Persian Empire, he reigned 559-529 BC. He seized Media in 550, went on to conquer Lydia, and his crowning success was the capture of Babylon. He was finally killed in battle against one of the tribes north of his Kingdom.
God stirred up Cyrus to build a Temple in Jerusalem . Cyrus told the Jews that any of God's people among the inhabitants of the former Babylonian Empire may go up to Jerusalem in Judah and build the temple of the Lord . So through Cyrus a total of 42,360 persons returned to Judah along with 5,469 gold and silver items, livestock and donations .
A clay cylinder was found in Babylon called the "Cyrus Cylinder." It is full of inscriptions giving record of Cyrus' capture of Babylon, and tells how the captives of Babylon were returned to their homelands. This is in line with the decree Cyrus issued in 538 BC, allowing the Jews to return home to Jerusalem, as described in the Bible. The cylinder is now in the British Museum.