Some Turk mercs, maybe?
Them Normans got around back in the day. Muslims owned and operated most of Spain. The Normans were HQed in France. Spain and France ain’t all that far apart.
Maybe there were some Turk free booters floating around the AO and got themselves hired by the Norman dudes.
It wouldn’t surprise me. There was seagoing trade from Constantinople to a lot of nooks and crannies in Britain throughout the so-called Dark Ages, and this was much later, after the Varangians had been working for the Byzantines for centuries. The Viking mercenaries helped run the saracens out of Sicily, and the Normans later established a short-lived kingdom there.