Norman Medieval Castles & Byzantium
The Normans were in fact descended from the Vikings who invaded that northern part of France and assimilated into the local community. Indeed, their ancestral Viking blood and thirst for conquest of new territories meant that England was not the only country to suffer their invasion.
The Normans were active right across the medieval world and in particular in Southern Italy, along the Dalmatian coast, fighting for and against the Byzantine Empire. As pilgrims made their way to and from the Holy Land there were resulting, seeminghly inevitable disputes into which stepped Norman mercenaries and the time they spent in this part of the world left its mark.
Take a look at the picture below: a Norman medieval castle with characteristic walls and strength but it is not a castle in France or England! This is an early Norman castle in Adrano, Southern Italy.
The key point here is that the medieval world was much more fluid and fragmented than we think.
It is easy for us to be swayed by the headlines of history. The truth of all history, not just medieval history, is that there is always a lot more to it than at first meets the eye.