Before 1208 [her father] Simon Dammartin (age 28) and [her mother] Marie Montgomery Countess Ponthieu (age 8) were married. She the daughter of William Montgomery IV Count Ponthieu (age 28) and Alys Capet Countess Ponthieu (age 47).

In 1240 [her future husband] Otto II Duke Guelders and Margaretha Cleves (age 22) were married. She by marriage Duchess Guelders. She the daughter of Dietrich Cleves V Count Cleves and Mathilda Dinslaken Countess Cleves. He the son of Gerard III Count Guelders and Margaret Reginar Countess Guelders. They were fourth cousins. He a great x 4 grandson of King William "Conqueror" I of England.

Before 1250 Raoul Coucy II Lord Coucy and Philippe Dammartin Countess Eu were married. She the daughter of Simon Dammartin and Marie Montgomery Countess Ponthieu (age 50). They were half second cousin twice removed.

In 1253 Otto II Duke Guelders and Philippe Dammartin Countess Eu were married. She by marriage Duchess Guelders. She the daughter of Simon Dammartin and Marie Montgomery Countess Ponthieu. He the son of Gerard III Count Guelders and Margaret Reginar Countess Guelders. He a great x 4 grandson of King William "Conqueror" I of England.

In 1276 [her son] Reginald I Count Guelders (age 21) and [her daughter-in-law] Ermengarde Luxemburg I Duchess Limburg were married. She by marriage Duchess Guelders. She the daughter of Waleran Luxemburg IV Duke Limburg and Judith Kleve Duchess Limburg. He the son of Otto II Duke Guelders and Philippe Dammartin Countess Eu. They were fourth cousins. He a great x 5 grandson of King William "Conqueror" I of England.

Raoul Lusignan II Count Eu and Philippe Dammartin Countess Eu were married. She by marriage Countess Eu. She the daughter of Simon Dammartin and Marie Montgomery Countess Ponthieu.

Enguerrand Coucy 4th Lord Coucy and Margaret Guelders Countess Cleves were married. She by marriage Lord Coucy. She the daughter of Otto II Duke Guelders and Margaretha Cleves. She a great x 5 granddaughter of King William "Conqueror" I of England.