Maria Eleonora I Boncompagni
Maria Eleonora I Boncompagni (1686–1745) was the Princess of Piombino, Marchioness of Populonia, Princess of Venosa and Countess of Conza, Lady di Scarlino, Populonia, Vignale, Abbadia del Fango, Suvereto, Buriano, Isola d’Elba, Montecristo, Pianosa, Cerboli e Palmaiolan, from 1733 until her death.
She was the oldest of six daughters to her mother Ippolita Ludovisi. She succeeded her mother as sovereign at her death in 1733. She was married to her uncle, Don Antonio I Boncompagni, who became Prince of Piombino by the right of his wife (1658–1721).