Surname: Basaraba, Koscian - is it Polish or Tatar?

Can anyone tell me if this is a Tatar surname?

The name seems to be of Romanian origin. Of course, after hundreds of years who knows where people end up.

I would be guessing it comes from Bessarabia
en.wikipedia.org/wiki/Bessarabia#Principality_of_Moldavia

60 people in Poland with this last name.

Here is another website:
genealogy.euweb.cz/balkan/basarab.html

Merged: Is the surname Koscian tatar?

Is the surname Koscian tatar?

Kościan: from kość "bone" or in Eastern Poland from the name Konstanty (diminutive Kostek). It's a Polish name, but can be used by a person of any ethnicity or religion.