The Maison Royale de Saint-Louis was a school for girls located in Saint-Cyr, France. During the 18th century, young noblewomen of France were enrolled in the school and were taught manners, etiquette, embroidery and music.
By the late 18th century, Maison Royale de Saint-Louis was maintained by headmistress Madame Levene, who kept strict rules and regulations for the well-being and behavior of her students. In 1778, the soon to be Grand Master of the French Templars Élise de la Serre was enrolled in the school.
In 1786, the Maison Royale celebrated the school's centenary with a huge fireworks display, a ceremony that King Louis XVI attended.
During her education at the school, Élise often caused trouble with her fights against the head pupil, Valerie, acts wherein she was occasionally punished by Madame Levene. Due to her disturbances, her father François was called to Madame Levene's office on 8 September 1787, to complain about his daughter's rebellion. This never did bear fruit for Élise's behavior worsened.
By January 1788, Élise was on the risk of expulsion and her father was called once again. However, Élise's tutor Frederick Weatherall attended the meeting instead.
Gossip spread across Maison Royale's students that Madame Levene had been visiting a "lover" at night in the woods. This "lover" was in fact her son, Jacques, the groundskeeper, which she kept a secret and met him in his lodge every midnight. This information was used by Élise to blackmail the headmistress for letter of request to her father. When Madame Levene noticed the young girl spying on her, she requested a student to get a hold of Élise's journal. Here, the headmistress learned her thoughts and plans to blackmail her.
Infuriated, she called Élise to her office and showed her the journal, explaining that her strictness was for her sake and revealed the truth about Jacques. She made a deal with the girl: Élise would stay quiet about what she saw and Madame Levene would send the letter of request to her father.
On 9 April 1788, Élise, her handmaiden Hélène, and a wounded Weatherall arrived at Maison Royale, requesting help from Madame Levene. The headmistress welcomed her student and her acquaintances warmly and fetched a doctor from Châteaufort to deal with Weatherall's gun wound. The headmistress and Jacques let the trio live in the groundskeeper's lodge, where Jacques fell in love with Hélène. Élise continued her education despite the other students' gossip about her disappearance.
Over the course of the French Revolution, Élise would occasionally return to the Maison Royale to discuss the Assassin-Templar war with Weatherall. Here, they trained and contacted allies to relinquish the Templar control from their enemies.
In September 1794, Élise's Assassin lover Arno Dorian traveled to the Maison Royale to return Élise's chest to Weatherall. However, their former ally Bernard Ruddock had followed Arno and betrayed him, attempting to kill him and Hélène on the order of the British Templars. Fortunately, Ruddock was killed by Weatherall before he could shoot Arno. With the permission of Hélène, the Assassin stayed in the Maison Royale during the years following her death.