The Merovingians were an aristocratic family during the “Holy Roman Empire” that commissioned a number of religious paintings. They had long, blonde hair, and therefore, many of the subjects of the religious paintings they commissioned (the first in history) had long hair and European features. They were also known as the “long-haired” dynasty and they believed that long hair was a mark of kingship, thereby accounting for Jesus’ long hair, even though he would have had short hair (as was popular during the time).
The sovereignty of the Holy Roman Empire right before the renaissance would have direct implications on what Italy, Duccio and Giotto (the two Italian painters who kicked off the renaissance by introducing perspective into paintings) painted.
The point: The Merovingians gave a lot of money to Duccio and Giotto and they are why Jesus is white with long hair, because thereafter the first painting they commissioned, Jesus is less Mediterranean or African and more European as per subsequent paintings and visual and oral depictions of him.