Benedict of Soracte recorded that Octavianus was the son of a concubine (Genuit (Alberic) ex his principem ex concubinam filium, imposuit eis nomen Octabianus), but his Latin is unclear.

[2] Sometime before his death in 954, Alberic administered an oath to the Roman nobles in St. Peter's providing that the next vacancy for the papal chair would be filled by his son Octavian, who by this stage had entered the Church.

[4] With the death of Pope Agapetus II in November 955, Octavian, who was the cardinal deacon of Santa Maria in Domnica, was elected his successor on 16 December 955.

[6][7] In around 960, John personally led an attack against the Lombard duchies of Beneventum and Capua, presumably to reclaim parts of the Papal States which had been lost to them.

Confronted by the sight of John marching at the head of an army of men from Tusculum and Spoleto, the dukes of Beneventum and Capua appealed for help from Gisulf I of Salerno, who came to their aid.

A treaty was secured between the two parties, and the price for Gisulf's non-interference was John agreeing that the papacy would no longer claim Salerno as a Papal patrimony.

In order to protect himself against political intrigues in Rome and the power of Berengar II, John sent papal legates in 960 to King Otto I of Germany, who had previously been granted the rank of patrician, asking for his aid.

There he met with John and proceeded to swear under oath that he would do everything to defend the pope: To thee, the Lord Pope John, I, King Otto, promise and swear, by the Father, Son, and Holy Ghost, by the wood of the life-giving cross, and by these relics of the saints, that, if by the will of God I come to Rome, I will exalt to the best of my ability the Holy Roman Church and you its ruler; and never with my will or at my instigation shall you lose life or limb or the honour which you possess.

The pope and the Roman nobility swore an oath over the buried remains of Saint Peter to be faithful to Otto, and not to provide aid to Berengar II or his son Adalbert.

In early 956, he wrote to William of Mayence, the papal legate in Germany, urging him to continue in his work there, especially against those who would "devastate the churches of God".

[27] Undeterred, the emperor and the council deposed John XII, who by this time had gone hunting in the mountains of Campania,[28] and elected Pope Leo VIII in his stead.

[29] An attempt at a revolt in support of John was mounted by the inhabitants of Rome even before Otto I left the city, but was put down with a large loss of life.

According to Liudprand of Cremona, John died whilst enjoying an adulterous sexual encounter outside Rome, either as the result of apoplexy, or at the hands of an outraged husband.

[34] He was depicted as a coarse, immoral man in the writings which remain about his papacy, whose life was such that the Lateran Palace was spoken of as a brothel, and the moral corruption in Rome became the subject of general disgrace.

It is for this purpose that Liudprand of Cremona, a partisan of the Holy Roman Emperor Otto I, gives an account of the charges levelled against him at the Synod of Rome in 963: Then, rising up, the cardinal priest Peter testified that he himself had seen John XII celebrate Mass without taking communion.

For example, Ratherius of Verona wrote: What improvement could be looked for if one who was leading an immoral life, who was bellicose and perjured, and who was devoted to hunting, hawking, gaming, and wine, were to be elected to the Apostolic See?

So according to fiercely anti-Catholic Louis Marie DeCormenin: John XII was worthy of being the rival of Elagabalus ... a robber, a murderer, and incestuous person, unworthy to represent Christ upon the pontifical throne ...

The son of the glorious Alberic thus fell a sacrifice to his own unbridled passion, and to the anomalous position which he held as Prince and Pope at the same time.

[37]Even Horace Mann, a papal defender, was forced to acknowledge: There cannot be a doubt that John XII was anything but what a Pope, the chief pastor of Christendom, should have been.