UFO fans are convinced that a book published in 1716 offers proof that aliens have been visiting our planet for centuries - in the form of a picture of a flying saucer.

The book - Funccii liber de coloribus coeli by Johann Caspar Funcke, was found by an antique bookseller who sent an image to UFO website The Black Vault.

He claims that other books by the same author also show mysterious disc-shaped craft.

The unnamed finder says, ‘The leather had been soaked and contaminated so it to be removed. The frontispiece itself still has water damage. When I opened the volume up, I almost lost my poker face. Fortunately, the owner thought it worthless even when new and gave it to me for fifteen dollars.’

Nigel Watson, author of the UFO Investigations Manual says: ‘Flying saucers, UFOs and other weird objects in the sky have been depicted throughout the history of humanity. ’

'What appear to be UFOs and aliens appear in the cave paintings of ancient man, the reigious paintings of the Renaissance period and in the works of chroniclers and storytellers.’

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'Some of the most striking UFO images appear in Renaissance art. As an example, a painting titled The Crucifixion depicts two spherical flying craft that plainly have a pilot inside them. It is of 1350 vintage and hangs over the altar in the Visoki Decani Monestry, Yugoslavia.’

'In the 15th Century, The Madonna with Saint Giovannio, the artist Domenico Ghirlandaio depicts a disc-like craft with rays shooting out of it over the left shoulder of Mary. A man with a dog behind Mary are shown looking at this aerial object.’

'The Baptism of Christ painted by Aert De Gelder in 1710 is a stunning vision of a circular craft beaming rays of light that illuminate Jesus and John the Baptist. It can be viewed at the Fitzwiliam Museum Cambridge.’

'An explanation for these Biblical paintings is that they are symbolic representations of angels and that the beams of light from them represent the Holy Spirit. These beams of light can also represent the miraculous impregnation of Mary that led to the birth of Jesus. Ironically, people today are literally seeing objects like this in the sky and associate their activities with the concept of ancient astronauts that it is speculated, we worshipped as Gods in the past.