When Otto II sent an imperial representative, Count Sicco, to secure his release, Crescentius I and Cardinal-Deacon Franco Ferrucci, who would subsequently become Boniface VII, an antipope, had Benedict murdered while still in prison.

When Otto the Great died and Otto II took over, Crescentius led the rebellion against the imperial regime which would eventually lead to the installment of Franco to the papacy.

With the help of Crescentius ’ sons, John and Crescentius II, along with his Greek followers, Boniface had Pope John XIV imprisoned in Castel Sant ’ Angelo.

Until the conclusion of the council of Pavia in 997, Gregory V had a rival in the person of the antipope John XVI ( 997 – 998 ), whom Crescentius II and the nobles of Rome had chosen against the will of the youthful Emperor Otto III, Gregory's cousin.

The revolt of Crescentius II was decisively suppressed by the Emperor, who marched upon Rome.

John XVI fled, and Crescentius II shut himself up in the Castel Sant ' Angelo.

The Castel Sant ' Angelo was besieged, and when it was taken in 998, Crescentius II was hanged upon its walls.

Otto III also sought to reestablish Imperial control over the city of Rome, which had revolted under the leadership of Crescentius II, and through it the papacy.

After pardoning him and leaving the city, Crescentius II again rebelled against the Emperor, deposing Gregory V and installing John XVI as Pope.

Otto III returned to the city in 998, reinstalled Gregory V, and executed both Crescentius II and John XVI.

With the aid of the sons of Crescentius the Elder, Crescentius II and John Crescentius, Boniface VII was about to imprison John XIV in the Tomb of Hardian.

With Otto III was still a child and his regent, his mother the Empress Theophanu, absent from Italy, Crescentius II took the title of Patricius Romanorum ( Patrician of the Romans ) and became the effective ruler of the city, though he did not act entirely independent of the imperial authority, presenting himself as a lieutenant of the Emperor.

Though the particulars of the election are unknown, it is likely Crescentius II played a key role in the process.

For a number of years Crescentius II exercised authority over the city, severely limiting the autonomy of the pope in the process.

When the Empress Theophanu was in Rome between 989 and 991, Crescentius II nominally subordinated himself to her, though maintained his position as ruler of the city.

Otto III not only intended to be crowned Emperor but also to come to the aid of Pope John XV, who had been forced to flee Rome by the city's de facto ruler Crescentius II.

While Otto III was in Pavia, Crescentius II, fearing the king's march on Rome, reconciled with Otto III and agreed to accept his nominee as pope.

A number of the rebels, including Crescentius II, were banished for their crimes.

In particular, while Crescentius II was pardoned by Otto III, he was deprived of his title of Patricius but was permitted to live out his life in retirement at Rome.

Otto III's soldiers breached the stronghold and executed the rebellious Crescentius II.

In September 996, a few months after receiving a pardon from Otto III, Crescentius II meet with the Archbishop of Piacenza John Philagathos, a former adviser to the late Empress Theophanu, to devise a plan to depose the newly installed Pope Gregory V. In 997, with the active support of Byzantine Emperor Basil II, Crescentius II led a revolt against Gregory V, deposed him, and installed John Philagathos as Pope John XVI, an antipope, in April 997.

Despite submitting to Otto III, Crescentius shut himself in his family's stronghold, the Tomb of Hadrian, out of fear of retribution.

Towards the end of April, the stronghold was breached, and Crescentius II was taken prisoner and executed by decapitation.

The Nationalist faction, previously headed by Crescentius and now headed by his two sons, that had helped him rise to his papal status was now not so much Byzantine as it was national-Roman.

The power held by Sergius IV was often overshadowed by John Crescentius III, the ruler of the city of Rome at the time.

Some historians have claimed that Sergius IV was essentially a puppet ruler for Crescentius III.

There was some suspicion that the Pope was murdered, as he died within a week of Crescentius, considered by many to have been his patron.

The second work, Memoriale Desiderio Animae de Gestis et Verbis Sanctissimi Patris Nostri Francisci (" The Memorial of the Desire of a Soul Concerning the Deeds and Words of Our Most Holy Father Francis " often just called the " Second Life ") was commissioned by Crescentius of Jessi, the Minister General of the Franciscan Order sometime between 1244 and 1247, and reflects changing official perspectives on Francis in the decades after his death.

At the time he mounted the papal chair, Crescentius II was Patrician of Rome, significantly hampering the pope's influence, but the presence of the Empress Theophanu, regent for her son, Holy Roman Emperor Otto III in Rome from 989 to 991 restrained Crescentius ' ambition.

In 999, Otto made a pilgrimage from Gargano to Benevento, where he met with the hermit monk Romuald and the Abbot Nilus the Younger ( then a highly venerated religious figure ) in order to atone for having executed Crescentius II after promising his safety.

Following his death, the Roman people suggested that Stefania, the widow of Crescentius II, had made Otto III fall in love with her and then poisoned him.

John XVII was nominated to the papacy by John Crescentius, a Roman noble who held power in the city in opposition to Emperor Otto III.

John XVII's successor, Pope John XVIII, was also selected by Crescentius.

After the Emperor's death, the youthful Emperor Otto III ( 983 – 1002 ) came to the aid of Pope John XV ( 985 – 996 ) in 996, to put down the rebellion of a faction led by the rich and powerful Roman nobleman Crescentius the Younger.

Once Otto III had returned to Germany, the faction headed by Crescentius II violently unseated Gregory V and, with the active support of the Eastern Emperor, Basil II, acclaimed John as Pope John XVI ( 997 – 998 ).

The revolt of Crescentius II was decisively suppressed by Otto III, who marched once again upon Rome, in February 998.

Several individuals named Crescentius who appear in the very scanty documentation of the period have been grouped together by historians as the " Crescentii.

In 996 he was in the retinue of the king on his journey to Italy, together with Otto III he pushed the election of Pope Gregory V against the resistance of the Roman nobility led by Crescentius the Younger and was present at the consecration and at the synod convened a few days later.

Marinus was succeeded by his son Crescentius, who defended his uncle the pope resolutely from imperialist attacks.

When Otto II sent an imperial representative, Count Sicco, to secure his release, Crescentius I and Cardinal-Deacon Franco Ferrucci, who would subsequently become Boniface VII, an antipope, had Benedict murdered while still in prison.

When Otto II sent an imperial representative, Count Sicco, to secure his release, Crescentius I and Cardinal Franco Ferrucci had Benedict VI murdered while still in prison in 974.