Question: Who is Peter, Constable Of Portugal's paternal grandfather?
Sentence (from "Peter, Duke of Coimbra"): Infante D. Pedro, Duke of Coimbra , (9 December 1392 – 20 May 1449) was a Portuguese "infante" (prince) of the House of Aviz, son of King John I of Portugal and his wife Philippa of Lancaster, daughter of John of Gaunt.
Relevant evidence: Yes