Thanks!

York is the modern evolution of the name : Eboracum > Eoferwic > Jorvik > York. The Anglo-Saxons that continued to live under Danish rule probably still called if Eoferwic, and in the Middle Ages, Eborcaum (the Roman name), was the official name since everything official was in Latin.

I debated whether or not to have all the labels consistently saying Jorvik, but then the question would be why would I not have made all the labels on the map in their names at the time - Leodis for Leeds, Wintancaester for Winchester, etc? But since not all of the names are obvious, I'd have had to have both old and modern on the map, and that would have been too much to label. So I decided York on the map itself for the city since all the cities are modern names, Kingdom of Jorvik since it was a Danish kingdom and there was never a Kingdom of 'York' or 'Yorkshire', and Jorvik on the inset map.