Normans in Ireland- it's where my surname comes from for one. A simple progression (Burgo ?)-> de Burgh-> de Burca->Burke. There was never enough land for the grasping Normans, and they took it anywhere they could, doing freelance incursions into Ireland almost as soon as they'd sobered up from Hereward's wake. Several apparently 100% Scottish names are actually Norman too.

I wonder if they left traces of their names in other areas they operated in, like Sicily and Constantinople?

Greg- any evidence of Roman incursions into Ireland? I know there's stuff like silverware, but that's usually put down to pirate raids.