Guillaume was the son of Nicolas de Saint-Omer and Margit Árpád. The date and place of his birth have not been found.
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Margit Árpád |
Béla III Árpád |
Géza II Árpád |
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Euphrosyne de Kiev |
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Agnès de Châtillon-sur-Loing |
Renaud de Châtillon-sur-Loing |
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Constance de Hauteville |
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