John II of Loon
John II (Johann II), (d. 1438), Lord of Jülich, Heinsberg and Löwenberg (Herr zu Julich und Heinsberg), son of Godfrey de Heinsberg, Count of Looz, and Philippa of Jülich, daughter of William V, Duke of Jülich, and Joanna of Hainaut. Although John was the first son of Godfrey, he did not inherit the countship of Looz, the title instead going to Arnold of Rumingy.
- Johann III (d. before 1441), married Walpurg von Mörs. Their granddaughter Johanna was the Countess of Nassau-Saarbrücken.
- Wilhelm I (d. 24 April 1439), married Elizabeth von Blankenheim, daughter of Gerhard IX, Count of Blankenheim, great-great-grandson of Gerard I, Count of Durbuy.
- John of Heinsberg (d. 1459), Bishop of Liège (1419-1455)
- Philippa (d. 1464), married Wilhelm von Wied-Isenburg.
John and Anna had two children:
- Maria of Loon-Heinsberg, married John IV, Count of Nassau
- Jacoba of Loon-Heinsberg (d. 1466), Abbess of Thorn.
Arlette Laret-Kayser, Entre Bar et Luxembourg : Le Comté de Chiny des Origines à 1300, Bruxelles (éditions du Crédit Communal, Collection Histoire, série in-8°, n° 72), 1986
Marchandisse, Alain, La fonction épiscopale à Liège aux xiiie et xive siècles: étude de politologie historique, Bibliothèque de la Faculté de Philosophie et de Lettres de l'Université de Liège, 1998