At the age of eleven she was married to the twenty-year-old King
          Diniz of Portugal. Eight years later she gave birth to a daughter to
          be followed by a son a year after that.
              Diniz was a strong and effective ruler but also a bad husband. He
          neglected her and was unfaithful. However, she assisted him and
          founded a hospital, a 'rescue home' for women and an orphanage for
          foundlings. In later years she tried to reconcile her husband and
          their son; but Diniz, suspecting her motives, banished her for a while
          to a remote fortress.
              In 1325 she became a widow and retired to Coimbra where she lived
          near a Poor Clare convent she had founded. Here she devoted her time
          to a religious life and the poor of the area. In 1336 her son, King
          Alfonso IV of Portugal, went to war with King Alfonso XI of Castile
          and Isabel followed her son's army determined to make peace. In this
          she succeeded but she had asked too much of herself and she died
          before she could return to Coimbra.
 

Source: Leo van de Pas