Maria Antonia von Branconi, née Elsener was the official royal mistress of Charles William Ferdinand, Duke of Brunswick-Wolfenbüttel between 1766 and 1777.
She was the daughter of German-Italian parents and was raised in Naples.
Branconi was by her contemporaries known as the most beautiful woman in Germany. She entered into a relationship with him and followed him back to Brunswick in Germany, where she became his official favorite. The couple had a child, Karl Anton Ferdinand (1767–1794).
Branconi lived in her own palace at Wilhelmstrasse in Brunswick, where she entertained a large social life.
The relationship with Karl was finished when he entered into a relationship with Luise Hertefeld in 1777. Branconi made several trips in Europe and lived in Paris 1787–1791.
She had a son, Jules Adolph Marie, in a new relationship in 1788. Branconi was acquainted with the professors at the university of Brunswick, among them JJ Eschenburg and Johann Arnold Ebert.
She was also acquainted with Johann Wilhelm Ludwig Gleim, Sophie von Louisiana Roche and Johann Caspar Lavater and corresponded with Goethe from 1780.