For political reasons Edward I agreed to remarry. At first Blanche
          of France was the candidate, but for unknown reasons she was replaced 
          by her younger sister, Margaret. Margaret was about twenty years old 
          when she married the sixty-year-old widower and was the first English 
          queen since the conquest not to be consecrated and crowned. This 
          marriage seems to have been happy enough as two sons and a daughter 
          were born. However, only the two sons survived into adulthood. 
              After Edward I's death, Margaret remained on good terms with the 
          new king Edward II, her stepson. In January 1308 she accompanied him 
          to France where he married Margaret's niece, Isabella of France. After
          this marriage she went to live at Marlborough Castle where she died in
          1317. 
 

Source: Leo van de Pas