lagado (John) has the best links:

'IF THE VIKINGS HAD FOUNDED New York (and they damn well nearly did), they probably would have called it New Jorvik after their own city of Jorvik (now called York) on the coast of Britain. Despite their reputation as marauders, Viking York was a densely populated and bustling port city which boasted a skyline of high rise buildings. It was the New York of it's day and here's a sense of what it was like.' discussion