The Nimrud Lens is a 3,000-year-old piece of rock crystal discovered in 1850 by Sir John Layard in the Assyrian palace of Nimrud in what is now Iraq. Since its discovery more than a century ago, scientists and historians continue to debate its use, with one prominent Italian professor claiming that the lens was used by the ancient Assyrians as part of a telescope. This would explain why the Assyrians knew so much about astronomy.

The Nimrud Lens, which has been dated to between 750 and 710 BC, is made of natural rock crystal and has a slightly oval shape. It was roughly ground, apparently on a lapidary wheel. It has a focal length of about 11 cm from the straight side and a total focal length of about 12 cm.

This would correspond to a magnification of up to three times that which a cluster can provide. There are twelve cavities on the surface of the lens that opened up during grinding and that contained some kind of liquid trapped in the raw crystal. The found lens is said to be able to focus even sunlight, although experts are still thinking about this fact.

The original use of the Nimrud lens is widely debated. Some believe it served as a magnifying glass or as a burner to start fires by concentrating sunlight. Others then suggest that the lens was part of a telescope.

But these theories are shattered by the British Museum's claim that the Nimrud lens had little or no practical use. And although this piece of rock crystal was carefully cut and polished and undoubtedly has optical properties, the scientists come to the unusual conclusion that the optical properties were probably accidental.

A lens that can rewrite history

The found lens can thus rewrite not only all claims made so far, but actually the entire history. For there is still no evidence that the Assyrians used lenses either for magnifying or for making fire.

This makes it much more likely that it is a piece of marquetry. A kind of work of art that could have served as a piece of furniture. However, many disagree with this statement.

Sir John Layard suggested that Assyrian artisans used lenses as magnifying glasses to create intricate and minute engravings. Exactly the ones found on seals and clay tablets using cuneiform writing. However, experts in Assyrian archeology are not convinced. They claim that the lens is of such poor quality that it would be a poor vision aid.

Some scientists believe that the lens was burning glass that was used to focus the sun's rays.

An outstanding researcher and author Robert Templewho has spent a lot of time studying ancient lenses, writes in his fascinating book The Crystal Sun that "technology is forbidden when it is not allowed to exist".