Question: Who is the paternal grandfather of Jan I Of Opole?
Sentence (from "Bolko IV of Opole"): Bolko IV of Opole (1363/67 – 6 May 1437), was a Duke of Strzelce and Niemodlin during 1382–1400 (with his brothers as co-rulers), Duke of Opole from 1396 (until 1400 with his brother as co-ruler, except Olesno).
Relevant evidence: No