On 26 April 1709, Marie Louise was married to
Johan William, Prince of Orange. He was the eldest surviving son of
Henry Casimir II, Prince of Nassau-Dietz, and
Henriëtte Amalia of Anhalt-Dessau; he had inherited his title in 1702 from the childless
William III, Prince of Orange, due to his descent from both
William the Silent and
Frederick Henry, Prince of Orange. The events behind their betrothal began after
Johan William was almost killed by cannon fire and roundshot on two occasions. His mother,
Henriette Amalia, perhaps realizing how vulnerable her son was, quickly began looking for a suitable bride to ensure an heir. In the end, the choice came down to two German princesses. She apparently informed him that he should think of the choice as between two chairs, and that he should choose the most comfortable of the two. Johan duly traveled to
Hesse-Kassel and became engaged to the 20-year-old Marie Louise within a week. He did not even bother meeting the other candidate. The main factor in this decision was probably that Marie Louise's father was a trusted general under the well-respected
Duke of Marlborough. Marie Louise was not considered attractive, as her features were heavy and her face was dominated by a large nose. She was however very charming, and greeted those of all ranks with natural friendliness and sincere concern for their well being. They had two children before his untimely death by drowning on 14 July 1711, the youngest of whom was born after his death.
William Charles Henry Friso's birth was met with great relief by the
Frisians, and he automatically inherited the title Prince of Orange. ==First regency==