Afonso I of Portugal
In 1178 Ferdinand II invaded the Kingdom of Castile. He seized the municipalities of Castrojeriz and Dueñas (both formerly lands of Teresa Fernández de Traba's first husband) before Alfonso VIII could have put these fortresses on alert, while the Castilian sovereign allied himself with Afonso I of Portugal, who sent his son, Infante Sancho, to fight against the King of León.