Marguerite de Busbach, born in Luxembourg on 20 January 1579, was a member of a wealthy and notorious family of the 16th and 17th centuries. She was the daughter of Christophe de Busbach, a literate councillor at the Provincial Council of Luxembourg, and Marguerite Drouxman of Trier. Already as a child, she was said to have great piety and virtue. In 1600 she married Melchior de Wiltheim, a lawyer in Luxembourg, who had been courting her for many years. The young woman gave birth to eight children, of whom only three survived, one boy and two girls. On 6 January 1621, Melchior de Wiltheim died of languor. The young widow, seeing this misfortune as a test of God's will, redoubled her religious zeal and, together with Anne-Marie de Mansfeld, founded the Order of the Congregation of "Notre-Dame" in the city of Luxembourg. This establishment was the first to offer free education to girls from non-noble families.
Marguerite de Busbach encouraged her two daughters, Régine and Elisabeth, to enter the novitiate of the Congregation. She herself broke with worldly life and entered the convent at the age of 52. From then on she took the name of Sister Monique. She was known and appreciated by many inhabitants.
After two years of serious illness, Sister Monique died in 1651. She is buried in the crypt of the convent, today the Protestant Church of the Holy Trinity.
● Madame Busbach, widow Melchior de Wiltheim, in religion Sister Monique, Foundress of the Monastery of Our Lady in Luxembourg/Author unknown.
● Auguste Neÿen: Busbach Marguerite de in: Biographie luxembourgeoise: Histoire des hommes distingués originaires de ce pays [... ], Luxembourg, 1860, Editions
● Pierre Brück, pp. 107-108.