The Cyrus Cylinder, discovered in 1879 and now in the British Museum, is a cuneiform document in the shape of a small barrel, commissioned by Cyrus the Great of Persia.

A certain amount of fraudulent material exists on the internet, for example that it confirms what the Bible says (Isaiah 44.23-45.8; Ezra 1.1-6, 6.1-5; 2 Chronicles 36.22-23): that in 539 BCE, the Persian conqueror Cyrus the Great had allowed the Jews to return from their Babylonian Exile.

Here is a legitimate scholarly page that discusses this fascinating document: here