[4] Under the agreement, the king of Castile promised that we would cede all the rights he held in the Algarve to the first male offspring of Alfonso III and Beatrice when the child was seven years old.

[5] Much more serious was the fact that when the nuptials took place, the Portuguese monarch was still married to Matilda II of Boulogne, who, in 1255, accused her husband before Pope Alexander IV of bigamy.

[5] Until her husband's death, Beatrice had great influence in the Portuguese court and supported the rapprochement of the kingdoms of Portugal and Castile.

When her mother died no later than 1267, she inherited her estates in La Alcarria which included Cifuentes, Viana de Mondejar, Palazuelos, Salmerón, Valdeolivas and Alcocer.

A charter kept at the Torre do Tombo National Archive in Lisbon documents the donation made by King Alfonso X of Castile to his daughter Beatrice of the villas of Mourão, Serpa, Moura with their castles and, on the same day, he also gave her the Kingdom of Niebla and the royal tithes of the city of Badajoz.