I want to know the answer to the following question:
WHen did they find the polish kingdom?
All the background I'm provided with is that "The szlachta traced their descent from Lech/Lekh, who probably founded the Polish kingdom in about the fifth century.:482 Lechia was the name of Poland in antiquity, and the szlachta's own name for themselves was Lechici/Lekhi.:482". Is that enough to answer the question?
Answer: yes