(12 July 1730–6 Feb. 1740)
The four-month conclave of 1730 was exceptionally contentious, with half the cardinals present being proposed at one stage or another. Eventually the Florentine Lorenzo Corsini was unanimously chosen. Born on 7 Apr. 1652, eldest son of a noble family enriched by commerce, he had his schooling at Florence, and then studied at the Roman College and at Pisa, graduating doctor of laws in 1675. On his father's death in 1685 he decided on an ecclesiastical career, renounced his inheritance, and entered the curial service, in which he had the help of relatives, in particular his uncle Cardinal Neri Corsini, with whom he lived while in Rome. His wealth enabled him to purchase useful positions, and in Apr. 1690*Alexander VIII named him titular archbishop of Nicomedia, though he was not yet a priest: he was ordained in May and consecrated bishop in June. The following year he was designated nuncio to Vienna, but the emperor, irritated that his nominees had not received the purple, declined to receive him. He therefore remained in Rome, gaining financial expertise as treasurer (1696) of the apostolic chamber. In May 1706 he was made cardinal priest of Sta Susanna by Clement XI, and at several conclaves was among the principal papabili, or cardinals considered in the running for election. His new family home in the Palazzo Pamphili, on the Piazza Navona, was the centre of Rome's scholarly and artistic life: he was himself an accomplished violinist. He took the name of his patron Clement XI.
Aged 79, often bedridden with gout, blind from 1732, and from 1737 suffering from loss of memory, Clement relied increasingly on his immediate circle, especially on his nephew Neri Corsini, whom he named cardinal but who had little capacity for state business. He first had Cardinal Niccolò Coscia, Benedict XIII's evil genius, and his coterie brought to trial; Coscia was sentenced to a huge fine and ten years' imprisonment in Castel Sant'Angelo. He then made strenuous efforts to remedy the débâcle into which the finances and administration of the papal states had fallen. Among the measures he adopted were the revival of state lotteries, which Benedict XIII had banned, the issue of paper money, the restriction of the export of valuables, and new taxes on imports. A free port was created at Ancona, and attempts made to stimulate trade and industry. His endeavours were hampered, however, by corrupt administration, reduced revenues from the Catholic powers, and the losses resulting from the invasion of the papal states. At his death the burden of debt was still increasing. In addition, numerous favours improperly granted by Benedict XIII out of excessive goodness were cancelled or at least modified.
The decline in the papacy's international standing, noticeable in preceding reigns, continued under Clement XII; the powers coerced or ignored it at will. In 1731 he had to look on helplessly while Emperor Charles VI (1711–40) asserted suzerainty over Parma and Piacenza, which traditionally owed feudal allegiance to the holy see, on behalf of Don Carlos of Spain (later Charles III: 1759–88). He was a helpless spectator, too, in the War of the Polish Succession (1733–8), ineffectually backing first one candidate and then another, and having finally to acquiesce in a shift of power in Italy arranged over his head under the treaties of Vienna (1735 and 1738). Meanwhile the papal states were overrun by Spanish armies, the Roman population revolted against the recruitment of troops by the Spaniards, and in May 1736 Spain, followed by Naples, broke off diplomatic relations with the holy see. To restore them Clement had to make substantial concessions to the Spanish government and invest Don Carlos (1738) unconditionally with the kingdom of the two Sicilies. He felt obliged, because of a hostile plebiscite, to disavow the annexation of San Marino to the papal state, proclaimed by his legate in Oct. 1739. A bull addressed in 1732 to the Protestants of Saxony, where the ruling house had become Catholic in 1697, assuring them of undisturbed possession of secularized church properties in the event of their conversion to the Catholic faith, produced no results and has been cited as an illustration of his political naivety.