 The death of her son Ferdinand in 1265 made her next son, Louis, her heir in Ponthieu but around 1275 he, too, died, leaving two children.But according to inheritance customs in Picardy, where Ponthieu lay, Joan's young grandson John of Ponthieu could not succeed her there; her heir in Ponthieu automatically became her adult daughter Eleanor, who was married to Edward I of England.It does not appear that Joan was displeased at the prospect of having Ponthieu pass under English domination; from 1274 to 1278, in fact, she had her granddaughter Joan of Acre (the daughter of Edward I and Eleanor) with her in Ponthieu, and appears to have treated the girl so indulgently that when she was returned to England her parents found that she was thoroughly spoiled.