Question: Who is Gian Maria Visconti's paternal grandfather?
Sentence (from "Gian Maria Visconti"): Gian Maria Visconti (or Giovanni Maria; 7 September 1388 in Abbiategrasso – 16 May 1412) was the second Visconti Duke of Milan, the son of Gian Galeazzo Visconti and Caterina Visconti.
Relevant evidence: Yes