Her life as a courtier began in a turbulent time; when she was eighteen she was placed in the household of Louis XIV. At this time the Fronde was in full swing and Gabrielle was planted in the middle of it. However, she never seemed to have been in any real danger. Later she was transferred to the household of the King's brother, Philippe. The two of them developed a close relationship which only strengthened after Philippe became Duc d'Orléans.
At the age of 22 she was married to Claude Leonor Damas de Thianges and thus became the Marquis de Thianges. Gabrielle herself was not pleased with the match. As a daughter of the house of Rochechouart de Mortemart she felt that she was entitled to a "better" husband. As a a married lady she could take her place as a proper court lady and remained in the close circles of the royal family. It is quite possible that she was the mistress of Louis XIV from time to time although their relationship was more "on-off" than an actual thing. It certainly never got anywhere close to that of her sister, Madame de Montespan, who became the King's most famous mistress. However, whenever her sister was pregnant with the King's child - which was often - she would "lend her favours" to the King.
|Gabrielle, Marquise de Thianges|
She certainly was beautiful and well-aware of it. She would later describe herself to Madame de Sévigné as a "master-piece of nature". However, she was also obsessed with rank and the privileges that entailed. For instance she relished that she had been born into one of the finest noble families in France and spent her later years attempting to marry her own children into equally fine families.
Gabrielle and Athénais had a very close relationship which was somehow not particularly affected by the fact that they "shared" the King from time to time. Gabrielle took advantage of her sister's influence especially when it came to her children. Her favourite daughter, Diane, was married to the Duc de Nevers. However, she did not care much for her other daughter, Louise-Elvide, because she had not inherited the Mortemart good looks. Consequently, she was married to the sixty-year old Duke of Sforza.
Gabrielle had received a thorough education which had only brought out the infamous Mortemart wit. Her contemporaries praised her quick intelligence and her high spirits; one of these were Queen Christina of Sweden whom she met while travelling in France.
She also met another monarch, Charles II of England, when she accompanied Madame Henriette Anne, Duchesse d'Orléans on her way to meet her brother. Gabrielle went on well with the English King as well. It says something about her ability to charm that she could remain friends with the Duc d'Orléans who had done his uttermost to prevent his wife from leaving. Also, she was on good terms with Queen Marie Thérèse despite being both the sister of his maitresse-en-titre and occasionally his mistress herself. The Queen had become accustomed to the King's mistresses but the high humour of Madame de Thianges still endeared her to the Queen.
|Portrait presumed to be Gabrielle de Rochechouart|
Whether she was with her friends at court or keeping court herself on her estate the Marquise de Thianges became notorious for her wild parties. Her's was a personality of spontaneity and would frequently stay up until four or five in the morning.
Her marriage was not so amiable although she had four children by her husband. The couple had been living apart for a number of years when Gabrielle followed her sister's lead and separated from her husband in 1674. It was not a divorce per se which was not allowed by the Catholicism of her country but a "separation of bed and board". Instead, she set herself up quite as a single lady with her servants wearing her personal livery rather than her husband's.
With the separation the Marquise de Thianges was paid back her dowry; still, her husband did not protest to the procedure. The two of them would never renew their relationship but it seems that they parted ways voluntarily - contrary to her sister's troublesome husband.
By the end of 1679 the favour of Madame de Montespan was waning and the two sister plotted to provide the King with a new mistress as well as keeping him "in the family". Gabrielle suggested her beautiful, young daughter, Diane, but the King was not interested in her. To both her mother's and her aunt's surprise Diane was not interested in the King either - she was deeply in love with her husband.
The years she had spent at court had turned her into an adept courtier. When her sister fell from grace most expected the Marquise de Thianges to follow her into "exile". However, not only did Gabrielle manage to preserve her spacious apartment at Versailles she made an ally of the new mistress, Madame de Maintenon. As such she continued to play her part at court. While there she kept an eye on her nephews and nieces who were the offspring of the King and her sister.
Unfortunately, her previous lifestyle had taken its toll on her and while she kept her beauty her health deteriorated. By the time she had passed her fiftieth birthday she had to be carried by her servants to her supper.
Gabrielle died on 12 September 1693 in Paris.