One can admire the painting of the artist Sebastiano Mainardi (1466-1513)
at the Palazzo Vecchio in Florence. At first glance it shows a "normal" portrait with religious content.

...but amazingly one recognizes something else when looking closer.

It is clear that a flying object is portaited in the sky, being observed by a man.
Such "flying" objects are not a rarity in the paintings of the Middle Ages. Apparently,
phenomena of this type were nothing special.

On the altar fresco "The Crucifiction" in the church Visoki Decani Monestary (Kosovo)
objects fly mindlessly in the skies, and this also includes a crew.
The painting was painted in 1350.

On "Puerta de Ramos" the Tor the Cathedral of Salamanca can be found magnificent medieval ornaments.
 Between these, the attentive viewer can discover the unique representation of an astronaut!
appears to float in space, wearing a modern-looking Space Helmet, a supply bag,
boots and you can see also a supply hose. Twice this is astronaut found at the Cathedral gate.
A misreading of the representations is completely ruled out:
It is without question an astronaut with his equipment.
How is it possible
that such a clear presentation can be found on an up to 800-year-old cathedral?

Erscheinungen am Himmel im Mittelalter (engl.)