What is most striking about her life is her desire to reconcile people who are at odds with each other. The first time she contributed to a reconciliation was during her childhood, between her father D. Pedro and her grandfather D. Jaime, who did not speak to each other. D. Isabel’s delicate manner captivated both her father and grandfather, and both of them, through their common love for the Infanta, began to soften their relationship and shorten the distance that had been created between them. Later on she would bring two brothers closer: D. Dinis, her husband, and his younger brother, Afonso. On several occasions throughout her life, D. Isabel would intercede for peace between the brothers, and Infante D. Afonso was always very grateful to her sister-in-law for her pacifying role.

Santa Isabel also had great peacemaking intervention in international politics. She intervened in 1292 in the political disputes between her husband and the King of Castile, concerning the marriage of her daughter to the son of Sancho IV of Castile. In 1297, she helped King D. Dinis to establish the borders between Castile and Portugal, in the Treaty of Alcanizes, which remain practically intact until today, and this treaty was also formalized with D. Isabel’s seal. She also intervened in the conflicts between the Kingdoms of Castile and Aragon between 1300-1304 Later, in 1317, he sent ambassadors to Sicily and Naples, urging the two kingdoms to peace and begged the Pope to bring them to concord, having achieved her goals.