| b 1090, Of, , Ponthieu, France | Roger De Montgomery | d 1147, | Roger De Montgomery | |
| Robert II De Alencon | b 1005 | Guillaume II De Alencon | ||
| | b 1039 | Mabel De Alencon | Hildeburge De Beaumont | ||
| Guillaume III Duke Alencon, [Count] | d 1119 | b 1015 | ||
| |b 1055 | | | Guy I Count Ponthieu | ||
| |d 1172 | Agnes Countess Of Ponthieu, [Countess] | b 1036 | ||
| | | b 1066 | Ada | ||
| Guy II, Count Ponthieu | b 1006 | |||
| |Ida De Saint_Pol, [Countess] | |m 1145 | |||
| | | | | |||
| Alice Countess Burgundy, [Duchess] | ||||
| b 1055 | | | |||
| d 1191 | ||||
| 1 | < | Jean I Count Ponthieu |