Marozia, born Maria and also known as Mariuccia or Mariozza (c. 890 – 937), was a Roman noblewoman who was the alleged mistress of Pope Sergius III and was given the unprecedented titles senatrix ("senatoress") and patricia of Rome by Pope John X.
Edward Gibbon wrote of her that the "influence of two sister prostitutes, Marozia and Theodora was founded on their wealth and beauty, their political and amorous intrigues: the most strenuous of their lovers were rewarded with the Roman tiara, and their reign may have suggested to darker ages the fable of a female pope. The bastard son, two grandsons, two great grandsons, and one great great grandson of Marozia—a rare genealogy—were seated in the Chair of St. Peter." Pope John XIII was her nephew, the offspring of her younger sister Theodora. From this description, the term "pornocracy" has become associated with the effective rule in Rome of Theodora and her daughter Marozia through male surrogates.
Marozia was born about 890. She was the daughter of the Roman consul Theophylact, Count of Tusculum, and of Theodora, the real power in Rome, whom Liutprand of Cremona characterized as a "shameless whore... [who] exercised power on the Roman citizenry like a man."
At the age of fifteen, Marozia became the mistress of Theophylact's cousin Pope Sergius III, whom she knew when he was bishop of Portus. The two had a son, John (the later Pope John XI). That, at least, is the story found in two contemporary sources, the Liber Pontificalis and the Antapodosis sive Res per Europam gestae (958–62), by Liutprand of Cremona (c. 920–72). But a third contemporary source, the annalist Flodoard (c. 894–966), says John XI was brother of Alberic II, the latter being the offspring of Marozia and her husband Alberic I. Hence John too may have been the son of Marozia and Alberic I.