(15 Sept. 1644–1 Jan. 1655)
Born in Rome on 7 May 1574 into a long-established Roman noble family, Giambattista Pamphili studied at the Roman College with help from his uncle Cardinal Girolamo Pamphili, graduated doctor of laws in 1597, and entered on a legal career in the curia. After being a judge of the Rota 1604–21, where he became a friend of Alessandro Ludovisi, later Gregory XV, under Gregory's patronage he served as nuncio in Naples, and in 1625 accompanied Urban VIII's nephew Francesco Barberini on his legation to France and Spain. He clearly impressed Francesco, for Urban appointed him nuncio to Spain in 1626 and cardinal in Aug. 1627 (in petto: he announced the creation in Nov. 1629). His election, after a 37-day conclave, represented a reaction against Urban's pro-French tendencies; it was opposed by the French court, but Cardinal Jules Mazarin's (1602–61) veto arrived too late.
An old man, taciturn and mistrustful, slow in reaching decisions, Innocent at once turned on the Barberini, Urban VIII's hated relatives, setting up a commission to inquire into the riches they had amassed and meanwhile sequestering their possessions: two Barberini cardinals and other members of the family fled to France. Only the threats of Mazarin, the all-powerful French minister who took them under his protection, induced him to pardon them. Innocent himself, however, was not immune from nepotism, although none of the kinsmen he loaded with offices, wealth, and favours had the ability to fill the role of cardinal nephew (as the relative, usually a nephew, whom popes from Paul III until the late 17th century tended to employ as their closest collaborator was designated). Much more powerful and sinister in his court was Donna Olimpia Maidalchini, a sister-in-law of insatiable ambition and rapacity. The suggestion that their relationship was immoral was mischievous gossip, but her dominance was such that Innocent took no important decision without consulting her. But he did not use her son, Cardinal Camillo Pamphili, as secretary of state, who in any case in January 1647 resigned his cardinatial position to marry a wealthy widow. This post of secretary of state he gave to Cardinal Panciroli and then, after 1651, to Fabio Chigi (later Alexander VII), who was the first of the recognized secretaries of state with whom nuncios and legates corresponded directly and who themselves signed letters and instructions.
Innocent confirmed Chigi as representative of the curia at the congress for ending the Thirty Years War (1618–48) meeting at Münster. Like Chigi, he bitterly opposed the far-reaching concessions to Protestantism which Emperor Ferdinand III (1637–57) and Elector Maximilian I of Bavaria (1623–51) deemed unavoidable and included in the peace of Westphalia (24 Oct. 1648), and denounced them in the brief Zelus domus Dei; although dating it 26 Nov. 1648, he delayed publication until 20 Aug. 1650 so as not to aggravate the position of Catholics in Germany. His protest was brushed aside and had no practical effect. In spite of the peace, war dragged on between France and Spain and Innocent tried to hold a balance between them, although predisposed in favour of Spain, which he judged less of a threat to the church and Italy. Portugal having broken away from Spain in 1640, he declined formally to condemn the revolt, as Spain desired, but also refused (1648) to recognize John IV of Braganza (1640–56) as king, or to fill vacant sees with his nominees. Again, when Naples revolted against Spain in 1647 and the French ambassador urged him to seize the opportunity, as feudal lord, of incorporating the kingdom in the papal state, he preferred to temporize and see the restoration of Spanish rule; it was better to have a declining power like Spain installed in Naples than to let France gain a foothold. He granted financial aid to Venice and Poland in their struggle against the Turks, but had not enough money to assist Ferdinand III.