Something I was thinking about in Italy … we translate Venezia as Venice; Firenze as Florence; Roma as Rome. And yet the non-major cities we don't translate. Siena is Siene, Volterra is Volterra, Vernazza is Vernazza. This holds true across most foreign countries it seems. Moscow is a rough translation of Muskva, for example, but Vladivostok is Vladivostok.
Why translate large city names but not others? Why didn't we just call Firenze Firenze?
Most of these translations are extremely old, going back centuries. In the medieval and Renaissance periods, the big cities were the ones England traded with, and commerce was the main reason for travel. For the cities we had contact with frequently, we developed a rough equivalent that was kinder to our own tongue (accommodating laziness). The other cities, we didn’t bother with, because we never went there.
At least, that’s my theory.