(né Annibale Francesco Clemente Melchiorre Girolamo Nicola della Genga; 2 August 1760 – 10 February 1829) head of the Catholic Church and ruler of the Papal States from 28 September 1823 to his death in February 1829.For the correct biographical information, date and place of birth and surname, see Ph. Boutry, Souverain et Pontife.