(29 Apr. 1670–22 July 1676)
As none of the factions could muster a majority, and as France and Spain vetoed certain candidates, the conclave after Clement IX's death dragged on for almost five months before 79-year-old Emilio Altieri was elected. Born in Rome of a distinguished local family on 12 July 1590, he studied at the Roman College, took his doctorate in laws in 1611, worked as a barrister under Giambattista Pamphili (later Innocent X) when judge of the Rota, and was ordained in Apr. 1624. After three years as an auditor in the Polish nunciature, he served as bishop of Camerino 1627–54, which was relinquished by his brother for him, and was sent by Innocent X as nuncio to Naples in 1644. His tenure of this difficult assignment did not satisfy Innocent, and he was recalled in 1652. His fortunes revived, however, under Alexander VII, who in 1657 appointed him secretary of the Congregation of Bishops and Regulars and a consultor (expert adviser) of the Holy Office. A month before his death Clement IX named him cardinal, though because of Clement's death he was never invested with the red hat. After election he adopted his patron's name.
Aware that at his age he needed assistance, Clement assigned the role of cardinal nephew to Cardinal Paluzzi degli Albertoni, whose nephew had married Clement's niece (sole heiress of the Altieri), making him and his branch of the Paluzzi, as a token of relationship, adopt the name Altieri. The appointment was far from happy, for Paluzzi not only took complete control of affairs, reducing the secretaries of state to ciphers, but exploited the pope's kindness to accumulate offices and riches for himself and his family. The vast sums he spent extending the Palazzo Altieri so offended public opinion that Clement deemed it prudent never to visit it. Paluzzi could also be heavy-handed, as when in autumn 1674 he alienated the diplomatic corps by abolishing their tax immunities, thereby uniting against him even ambassadors of warring nations. As a price of reconciliation in May 1676 the French demanded that he create two of their candidates for the red hat. Instead the pope created six cardinals of his own choosing, which reconciled all other ambassadors to the holy see—they had been alarmed at too much French influence—but alienated the French king.
Clement was much preoccupied by the threat of the Turks to Poland, itself weakened by internal disorders, and strove to form a defensive alliance against them, even appealing (without success) to the Protestant king Charles XI of Sweden (1660–97). Both Clement and Cardinal Odescalchi (later Innocent XI) gave financial aid to John Sobieski (1624–96), who not only decisively defeated the Turks at the Dniester (11 Nov. 1673) but, the Polish throne having fallen vacant, was elected king (May 1674). Louis XIV of France (1643–1715) stood aside from the formation of a common anti-Turkish front, since he was preparing a war of conquest against Holland. For a time he led Clement to believe that it was a holy war for the restoration of Catholicism, so that the pope frowned on the intervention of Spain and on the military aid given by Emperor Leopold I (1658–1705) to the Dutch. By summer 1674 Clement realized that he had been deceived, and in Oct. 1675 sent envoys to Paris, Vienna, and Madrid to prepare for peace negotiations, but Louis did all he could to frustrate his efforts, which came to nothing. Meanwhile relations between king and pope were rapidly worsening, for when Louis infringed church privileges, confiscating church property and requisitioning religious houses so as to divert their income to military preparations, Clement's complaints fell on deaf ears. Louis's claim, however, to the unrestricted right of regalia (i.e. appointments to ecclesiastical offices and the income of vacant sees and abbeys), asserted in 1673 and 1675, did not apparently provoke any response from the holy see; Clement's successor was to inherit the problem.