He is and never was Emperor of the Holy Roman Empire . He is the first Emperor of Occident ( Carolingian Empire ) / . The term Holy Roman Empire was used only from the XIII century onward .
The Carolegian Empire was bigger, including all actual France, the Holy ... covered the same territories but not the main part of France ( East of the Rhones only )
Costume : he was not the kind of king wearing gold, silver, embroidery but simple one in linen and cape made of otter skin, according to Eginhard who lived at the court and wrote about that , he would make some effort when encountering ambassadors, wearing richer clothes .
But it's a nice painting job based on painting done hundreds of year after
Here a reconstitution of a Carolingian living at the time and fitting the description of Eginhard
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