Lord God of Heaven
Jerusalem, which is in Judah." (Ezra 1:2)
The Persians were largely followers of Zoroaster, but his religious system did bear some resemblance to the true monotheism of Israel. But Cyrus had been called, and even named, by God, long before he was born (Isaiah 44:28-45:6). When he conquered Babylon, the prophet Daniel was there (Daniel 6:28). The Jewish historian Josephus wrote that Daniel even became prime minister under Cyrus and was able to read Isaiah's remarkable prophecy to him, thus influencing him to send the Jews back to Jerusalem.
Image via Wikipedia There have also been other Gentile rulers who acknowledged God, even before Christ came. Nebuchadnezzar of Babylon, once hating God, finally was forced to confess that He was "the most High" and "King of heaven" (Daniel 4:34, 37).
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Another was the Queen of Sheba, who recognized "the LORD thy God" (again Jehovah Elohim, 1 Kings 10:9). Then there was the king of Nineveh and Assyria, who believed in God at the preaching of Jonah (Jonah 3:6-10). In fact, in the ages to come "the kings of the earth" will all "bring their glory and honour" to the Lord in the holy city (Revelation 21:24).