Around 1210 William Jülich III Count Jülich and Matilda Luxemburg Countess Jülich (age 18) were married. She by marriage Countess Jülich. She the daughter of Waleran Luxemburg III Duke Limburg (age 45) and Cunigunda Metz Countess Luxemburg. He the son of William Jülich II Count Jülich.

On 12 Mar 1237 William Jülich IV Count Jülich (age 27) and Margaret Guelders Countess Jülich were married. She by marriage Countess Jülich. He would, thirteen years later, marry her sister Richardis Guelders Countess Jülich (age 22); an example of Married to Two Siblings. She the daughter of Gerard III Count Guelders and Margaret Reginar Countess Guelders. He the son of William Jülich III Count Jülich and Matilda Luxemburg Countess Jülich. They were third cousins. She a great x 4 granddaughter of King William "Conqueror" I of England.

Before Jan 1250 William Jülich IV Count Jülich (age 40) and Richardis Guelders Countess Jülich (age 35) were married. She by marriage Countess Jülich. He had previously married her sister Margaret Guelders Countess Jülich; an example of Married to Two Siblings. She the daughter of Gerard III Count Guelders and Margaret Reginar Countess Guelders. He the son of William Jülich III Count Jülich and Matilda Luxemburg Countess Jülich. They were third cousins. She a great x 4 granddaughter of King William "Conqueror" I of England.

Before 13 Dec 1299 Gerhard Jülich V Count Jülich (age 49) and Elisabeth Brabant Countess Jülich were married. She by marriage Countess Jülich. He the son of William Jülich IV Count Jülich and Richardis Guelders Countess Jülich. He a great x 5 grandson of King William "Conqueror" I of England.

William Jülich II Count Jülich and Marie Guelders Duchess Jülich were married. She by marriage Countess Jülich. She the daughter of Reginald "Black" II Duke Guelders and Sophia Berthout Berthout.