Aurora can appear in different forms. What you are thinking of tends to be the ribbon/curtain appearing ones, but they can also appear as sheets of light, or pillars etc. I had a quick look through online images of aurora and this one could be seen as a red shield embedded in the sky (at a stretch).


One thing to bear in mind is that Aurora are not common at mid latitudes, and tend to only reach mid latitudes with really strong solar events. For example, during the 1859 Carrington event aurorae reached as far south as Hawaii. One can only imagine that if a single solar event that is estimated to be greater in magnitude than the Carrington event thought of the shapes in the sky at that time. Whether paredolia played a part in the image of shields, or just people trying to find a description for what they were seeing, i am sure it was used for "propaganda" or portents of providence or omens etc, just the same as novae, supernovae and comets were often seen as portents for kings and rulers etc. In other words is not what they would appear like to us, but rather how they could appear to teh eyes of people living in the 9th century. For example, we could look at a cloud and think it looks like Micky Mouse, but the same cloud may appear as a different object to someone from the 9th century.

There is no proof that Charlemagne's shields were aurora, but given that we have evidence consistent with a large solar event, it is likely that the record of these shields (as well as other events in other annals and chronicles) are recording aurorae.

Jonny



The path to good scholarship is paved with imagined patterns. - David M Raup