(4 Dec. 963–1 Mar. 965)
When the Roman synod of 4 Dec. 963 presided over by Emperor Otto I (962–73) deposed John XII (955–64) in his absence, the man elected by acclaim, with Otto's approval, was Leo, son of the notary John, an experienced Lateran official of exemplary character, chief notary (protoscriniarius) of the church. A layman, he was at once installed in the Lateran, in spite of canonical impropriety rushed through the lower orders in a single day, and consecrated by the bishops of Ostia, Porto, and Albano on 6 Dec., the rites used (for the first time in the case of a pope) being the revised ones introduced to Italy by Otto. It is likely that before consecration he swore fealty to the emperor, and it has been argued that the section of the ‘Ottonian privilege’ prescribing such an oath was inserted at this date. The legitimacy of Leo's pontificate, at least until John XII's death, has been contested; it depends on the validity, debated among canonists, of John's deposition.
Neither Otto's masterful rule nor, apparently, the choice of Leo was popular, and on 3 Jan. 964 a revolt threatening their lives, instigated by John XII at Tivoli, had to be crushed by the imperial troops. Anxious to halt the bloodshed, Leo unwisely persuaded Otto to release the hundred hostages the Romans had given him and be content with a renewed oath of loyalty. So far from winning Leo support, this led, when the emperor and his forces left Rome in mid-Jan., to violent disturbances which eventually forced the pope to seek refuge in the imperial court and enabled John to resume the reins of authority. At a synod in St Peter's on 26 Feb. he deposed and excommunicated Leo as a usurper of the holy see, uncanonically ordained, and guilty of perfidy to his lawful pope. Anyone he had ordained was compelled to confess that his orders were void.
On John's death (14 May 964) the Romans, ignoring Leo, besought the emperor to be allowed to elect the cardinal deacon Benedict. For Otto the restoration of Leo involved his personal prestige, and he flatly refused. The Romans notwithstanding elected and enthroned Benedict as Benedict V, and only gave in and surrendered him when Otto's army besieged the hunger-stricken city. Otto re-entered it on 23 June and reinstated Leo, who a few days later held a synod which deposed and degraded Benedict.
Apart from a few routine decisions little else is known of Leo's reign. Three documents attributed to him (the Cessatio donationum, the Privilegium maius, and the Privilegium minus), which purport to restore to Otto and his successors a number of territories in the patrimony of St Peter, as well as granting them the right to nominate and instal archbishops and bishops, have been shown to be 11th-century forgeries by Italian supporters of Emperor Henry IV in the investiture struggle; they reflect the conviction that Leo was the mere creature of Otto.
LP ii. 246–50JW i. 466–70, ii. 706MGConst 1: 532–6 (deposition), 663–78 (forged privileges)ZPR 129–50DBI lxiv. 506–7 (A. Piazzoni)DTC ix. 317–20 (É. Amann)Seppelt ii. 367–72Z1: 88–95, 235–51Z2: 150–54Th. Klauser, HJ 53 (1936), 186–9M. Andrieu, ‘La Carrière ecclésiastique des papes’, RevSR21 (1947), 109 f.W. Ullmann, The Growth of Papal Government (3rd edn., London, 1970), esp. 352–8EThC 87 (E.-D. Hehl)Levillain ii. 923 (R. Grosse)Partner 89–90