This is a fascinating piece. I would just like to add that many European artists from the 15th century onwards believed they were making depictions of Jesus based on an eye-witness account. A writen description of Jesus appeared in a letter written by a Roman official, Lentulus, supposedly a contemporary of Jesus, who gave this physical and personal description:
"He is a man of medium size; he has a venerable aspect, and his beholders can both fear and love him. His hair is of the colour of the ripe hazel-nut, straight down to the ears, but below the ears wavy and curled, with a bluish and bright reflection, flowing over his shoulders. It is parted in two on the top of the head, after the pattern of the Nazarenes. His brow is smooth and very cheerful with a face without wrinkle or spot, embellished by a slightly reddish complexion. His nose and mouth are faultless. His beard is abundant, of the colour of his hair, not long, but divided at the chin. His aspect is simple and mature, his eyes are changeable and bright. He is terrible in his reprimands, sweet and amiable in his admonitions, cheerful without loss of gravity. He was never known to laugh, but often to weep. His stature is straight, his hands and arms beautiful to behold. His conversation is grave, infrequent, and modest. He is the most beautiful among the children of men."
It is now widely accepted that the letter from Lentulus was a forgery; still, the letter was published widely across Europe and for a long time was taken as a direct eyewitness account. It is not surprising, then, that artists of the period used the description as the basis for their own representations of Christ and that, subsequently, a certain look established itself in paintings of Christ, as can be seen in works by numerous artists, from Jan van Eyck and Leonardo da Vinci.