steadier ground. Pius is best remembered in connection with the expansion of the Pio-Clementine Museum, which was begun at the suggestion of his predecessor Clement XIV; and with an attempt to drain the Pontine Marshes, but Pius VI did successfully drain the marshes near Citta della Pieve, Perugia, and Spoleto. He also restored the Via Appia. Pius VI also deepened and expanded the harbors of Terracina and Porto d'Anzio, a major center of Pontifical trade. Pius was a great patron of the arts and humanities; he also added a new sacristy to Saint Peter's Basilica. French Revolution At the outbreak of the French Revolution in 1789, Pius VI witnessed the suppression of the old Gallican Church as well as the confiscation of pontifical and ecclesiastical possessions in France. He saw the events as a sign of opposition against the social order ordained by God and also viewed it as a conspiracy against the church. The pope condemned both the Declaration of the Rights of Man and of the Citizen and the Civil Constitution of the Clergy and supported a league against the revolution. He issued two briefs - Quod aliquantum (1791) and Caritas (1791) - to condemn the ecclesiastical reforms that were proposed. 1791 marked the end of diplomatic relations with France and the papal nuncio, Antonio Dugnani, was recalled to Rome as a result. One of the reasons for the breach was the seizure by the revolutionaries of the Comtat Venaissin, ending 516 years of Papal rule in Avignon. King Louis XVI of France was executed via guillotine on 21 January 1793, and his daughter Marie Thérèse petitioned Rome for the canonization of her father. Pius VI hailed the late king as a martyr on 17 June 1793 in a meeting with cardinals, giving hope to a potential possibility of sainthood. In 1820, two decades following the death of Pius VI, the Congregation of Rites put an end to the possible sainthood since it was impossible to prove the king died for religious reasons rather than political ones. Pius VI argued that the main thrust of the revolution was against the Catholic religion and Louis XVI himself. He also wrote that the French revolutionaries abolished "the monarchy, the best of all governments". Deposition and death under Napoleon In 1796, French Republican troops under the command of Napoleon Bonaparte invaded Italy and defeated the papal troops. The French occupied Ancona