The art of the Dark Ages isn't dark. Those Byzantine basilicas with their mosaics must be among the sunniest buildings anyone erected before the invention of plate glass.
Early Christian art pictured Jesus as Apollo. He was clean shaven, curly-haired, androgynous. When he eventually grew a beard (in the 4th century) it wasn't because the artists were trying to picture him as a 1st century rabbi but because they were picturing him as Zeus. At the same time his feminine side got subcontracted to the Virgin Mary.
Early Christian art has no place for the crucifixion. Instead it celebrates Jesus's healing miracles. Early Christianity was a religion of liberation.