Polish Last names

Many people are puzzled by Polish last names. Especially they cannot find out why female’s surnames have a different spelling from male’s surnames. The situtation is simple when we have surnames finished with -ski. Then female last name will be -ska. Kowalski – Kowalska. However the situation is more difficult when we have different kinds of surnames. Some time ago I was researching records from 1700’s from town called Jasionka in Podkarpackie province. The last name I was researching was Szczurek. Female counterpart was written in five different ways: Szczurkowa, Szczurkowna, Szczurczanka, Szczurcząka, Szczurczonka.