While in St Peter's Basilica, I noticed a great monument near the south door, which was erected to honor the last three members of the Royal House of Stuart: James Francis Edward Stuart, his elder son Charles Edward Stuart, and his younger son, Henry Benedict Stuart. The Jacobites and Non-Juroring Clergy recognised these three princes as the true and rightful kings of England and Scotland. Its inscription reads:
To James III, son of King James II of Great Britain, to Charles Edward and to Henry, Dean of the Cardinal Fathers, sons of James III, the last of the Royal House of Stuart. 1819Under the inscription are two weeping angels, symbolising the lost hopes of the exiled Stuarts.
The three Stuarts are honorably buried in the papal crypt below. Opposite the monument to the Royal Stuarts in St. Peter's Basilica is a monument to Maria Klementyna Sobieska, wife of James Francis Edward Stuart and mother of Charles Edward Stuart and Henry Benedict Stuart.
Queen Christina of Sweden, the only monarch with a memorial in the church, lies entombed in the opposite pillar, across the nave. She abdicated in 1654 to convert to Catholicism.
Source and more information, Wikipedia: Monument to the Royal Stuarts.