Between the G.B. Gisleni monument and the main entrance is the monument to Maria Eleanora Buoncompagna Ludovisi, dated 1745. She was the Princess of Piombino, Marchioness of Populonia, Princess of Venosa and Countess of Conza. This is in pietra dura, or marquetry in colored stones. The work is so fine that it looks like a fresco.