Maria Flaminia Princess Odaleschi, a member of the Chigi family who died in 1771, is buried just outside of the Chigi chapel. She was the wife of Ferdinand Chigi and died during the birth of her 3rd child at the age of 20. The monument was designed by Paolo Posi, and the lion on her tomb is attributed to Francesco Antonio Franzoni. The monument celebrates the union of the two families, the lion symbolizes the Odescalchi and the mountain symbolizes the Chigi.