Question: Who is the paternal grandfather of Jan Ii The Mad?
Sentence (from "Jan I of Żagań"): Jan I of Żagań  (– 12 April 1439) was a Duke of Żagań-Głogów, since 1397 (until 1412 with his brothers as co-rulers), since 1403 Duke of Żagań, Krosno Odrzańskie and Świebodzin (again, until 1412 with his brothers as co-rulers) and since 1412 sole ruler of Żagań and Przewóz.
Relevant evidence: No