Hello,
For a while I thought the city name "Kraków" was plural, because the ending is, for a learner like me, typically a plural dopełniacz ending.
My Polish teacher was surprised that I thought so, and when I told her this ending doesn't look like singular, she looked for other words with this ending in mianownik, and she could not find any, besides other city names and such.
My theory was that it was plural dopełniacz that lost its first meaning and became mianownik, for example an old place named "wzgórze/miasto/zamek Kraków" becoming just "Kraków". So I checked for Kraków and it seems there are several theories, one of them being (source: Wikipedia):
In Polish, Kraków is an archaic possessive form of Krak and essentially means "Krak's (town)".
According to this explanation, I was quite right, except it would be an archaic singular form, not a plural form, otherwise it should be written "Kraks' (town)" I guess.
Do we know where these names come from, especially are they plural dopełniacz?
Thanks