Question: Who is the maternal grandfather of Peter I Of Aragon And Pamplona?
Sentence (from "Peter I of Aragon and Pamplona"): Peter continued his father's close alliance with the Church and pursued his military thrust south against bordering Al-Andalus taifas with great success, allying with Rodrigo Díaz de Vivar, known as "El Cid", the ruler of Valencia, against the Almoravids.
Relevant evidence: No