Duchess of Celle. The was born the daughter of Alexandre Desmier and Jacquette Poussard of Vandré, an impoverished French Huguenot family of minor French nobility. Considered a graceful beauty, she became lady-in-waiting in 1661 for the Duchess of Thouars and traveled to Kassel where the Duchess' son was to marry. There, she met Georg Wilhelm of Brunswick, Prince Calenberg, and his brother, Johann Friedrich. Both fell in love with her, but she was reluctant to commit to one of them. Being a mistress was unthinkable for her, but she became romantically involved with Georg Wilhelm. In 1658, Georg Wilhelm had signed a contract in which his brother, Ernst August and wife Sophie's children became his heirs in case he had no legitimate children, and in which he declared that he would never marry. This was done to prevent the family's land to be divided among many heirs. The Duchess of Thouar died in 1665, and Sophie of Hanover invited her to become her lady-in-waiting. A few months later, she and Georg entered a "marriage of conscience." Before the world she was his mistress, but the two saw themselves as married. Some sources claim she entered into a secret morganatic marriage with Georg. After a difficult labor on September 15, 1666, she gave birth to a daughter, Sophie Dorothea. On July 22, 1674, Emperor Leopold I created her Countess von Wilhelmsburg, and after a marriage ceremony on December 20, 1675, she was regarded to be Duchess of Brunswick-Celle. Besides having her marriage and her daughter legalized, she had an income. She had two more daughters, one in 1671 and another in August of 1676, but both died in infancy. Her daughter entered into a loveless marriage with a first cousin, Georg Ludwig, the future George I, King of Great Britain. After her daughter gave her two grandchildren, her daughter had an affair with Swedish Count von Koenigsmarck. Following the Count's mysterious disappearance on July 2, 1694 , her daughter was imprisoned at the Castle of Ahlden. Eventually, her daughter obtained a divorce from Georg Ludwig but she could never remarry or never see her children again, yet remained imprisoned. When her husband died in 1705, his wealth eventually became their son-in-law's. She fought the rest of her life for her daughter's release. She petitioned for help from Louis XIV, Queen Anne and Friedrich Wilhelm of Prussia without success. She wrote her daughter daily and was the only family member allowed to visit her daughter, which she did regularly. She supported many Huguenot families that had to flee from France after the Edict of Nantes was abolished. With her daughter still in isolation imprisonment for decades, she died nearly blind in the Castle of Celle. She mentioned 342 persons in her will.