When he was 10 the deception was discovered by Astyages, but because of his outstanding qualities he was allowed to live in exile. But in 550 the prophecy came true, and Cyrus overthrew his grandfather.
A variant of this legend, reported by Herodotus, has Cyrus as a feral child, at least for a while, cared for by dogs.
Cyrus was the king of Babylon who freed the Jews to return to their homeland, and he is remembered as a tolerant and wise king.