Hippolytus of Rome ( d. 235 ) is commonly considered to be the earliest antipope, as he headed a separate group within the Church in Rome against Pope Callixtus I. Hippolytus was reconciled to Callixtus's second successor, Pope Pontian, and both he and Pontian are honoured as saints by the Roman Catholic Church with a shared feast day on 13 August.

He was buried in the Church of Santa Maria in Monserrato degli Spagnoli, the Spanish national church in Rome, immediately below the tombs of Pope Callixtus III and Pope Alexander VI.

At the time, Alfonso was at odds with Callixtus III, who died shortly thereafter.

When at last successful, he was excommunicated by Pope Callixtus II for having expelled the monks of Saint-Gilles, who had aided his enemies.

The Borgia family originally came from the Kingdom of Valencia, and rose to prominence during the mid-15th century ; Cesare's great-uncle Alonso Borgia ( 1378 – 1458 ), bishop of Valencia, was elected Pope Callixtus III in 1455.

Accompanying Callixtus throughout France, he assisted Callixtus in his initial dealings with Holy Roman Emperor Henry V. As a well-known opponent of the emperor's right to select bishops in his territories ( the Investiture Controversy ), Lamberto was a natural choice for papal legate.

He was buried in the south transept next to the body of Callixtus II.

Pope Saint Callixtus I or Callistus I was pope from about 217 to about 222, during the reigns of the Roman Emperors Elagabalus and Alexander Severus.

His contemporary and enemy, the author of Philosophumena ( probably Hippolytus of Rome ), relates that Callixtus, as a young slave, was put in charge of collected funds by his master Carpophorus, funds which were given as alms by other Christians for the care of widows and orphans ; Callixtus lost the funds and fled from Rome, but was caught near Portus.

According to the tale, Callixtus jumped overboard to avoid capture but was rescued and taken back to his master.

Philosophumena claims that, denounced as a Christian, Callixtus was sentenced to work in the mines of Sardinia.

Hippolytus also accused Callixtus of the heresy of Sabellianism, but since Callixtus excommunicated Sabellius, the charge was clearly false.

The Basilica di Santa Maria in Trastevere was a titulus of which Callixtus was the patron.

It is possible that Callixtus was martyred around 222, perhaps during a popular uprising, but the legend that he was thrown down a well has no historical foundation, though the church does contain an ancient well.

Callixtus was honoured as a martyr in Todi, Italy, on 14 August.

Pope Callixtus III ( 31 December 1378 – 6 August 1458 ) (, ), né Alfons de Borja, was Pope from 8 April 1455 to his death in 1458.

He was raised to the papal chair in 1455 as Callixtus III at a very advanced age, as a " compromise candidate " in the papal conclave that year.

It takes its name from the deacon Saint Callixtus, proposed by Pope Zephyrinus in the administration of the same cemetery-on his accession as pope, he enlarged the complex, that quite soon became the official one for the Roman Church.

When Tertullian, a Montanist, furiously applied the term to some bishop with whom he was at odds ( either Pope Callixtus I or Agrippinus of Carthage ), c. 220, over a relaxation of the Church's penitential discipline allowing repentant adulterers and fornicators back into the Church, it was in bitter irony:

He afterwards became bishop of Châlons-en-Champagne, and took part in the dispute concerning investitures as a supporter of Pope Callixtus II, whom he represented at the conference of Mousson.

* 1124 – Pope Callixtus II

Twenty-five years after her execution, an inquisitorial court authorized by Pope Callixtus III examined the trial, pronounced her innocent, and declared her a martyr.

* 222 – Pope Callixtus I is killed by a mob in Rome's Trastevere after a 5-year reign in which he had stabilized the Saturday fast three times per year, with no food, oil, or wine to be consumed on those days.

With Gelasius ’ death, Lamberto became a close advisor of Pope Callixtus II.

Although Pope Callixtus II had made him Papal Legate of a number of Spanish provinces, Honorius informed Diego that he had been made aware of Diego ’ s ambitions and subtly advised him to keep his ambition in check.

Eventually Guido began his career in Rome as a subdeacon and a scriptor apostolicus under Pope Callixtus II.

# REDIRECT Pope Callixtus I

# REDIRECT Pope Callixtus II

# REDIRECT Pope Callixtus III

Statue of Pope Callixtus I, Cathedral of Reims

On 20 February 1456, Pope Callixtus III elevated two of his nephews to the position of cardinal.

simple: Pope Callixtus III

The following inscription honoring Sixtus was placed on his tomb in the catacomb of Callixtus by Pope Damasus I:

It is believed that the schismatic Hippolytus was still leading a rival Christian Congregation in Rome, and that he published the Philosophumena, an attack on Pope Urban's predecessor Callixtus.

However when excavating the Catacomb of Callixtus Italian archaeologist Giovanni de Rossi uncovered the lid of a sarcophagus which suggested that Pope Urban was in fact buried there.

When Callixtus followed Zephyrinus as Bishop of Rome, he started to admit into the church converts from sects or schisms who had not done penance ( as we learn from Hippolytus, Philosophoumena IX. 7 ).

Pope Telesphorus, Pope Hyginus, Pope Pius I, Pope Anicetus ( later transferred to the Catacomb of Callixtus ), Pope Victor I. Epigraphic evidence exists only for Linus, with the discovery of a burial slab marked " Linus " in 1615 ; however, the slab is broken such that it could have once read " Aquilinius " or " Anullinus ".

He was buried in the papal crypt of the Catacomb of Callixtus, on the Appian Way in Rome.

Callixtus I is elected as the sixteenth pope, but is opposed by the theologian Hippolytus who accuses him of laxity and of being a Modalist, one who denies any distinction between the three persons of the Trinity.

Callixtus is succeeded by cardinal Urban I.

Pressures building within the Curia, together with ongoing conflicts among the Roman nobility, would erupt after the death of Callixtus II in 1124.

These cardinals were reluctant to meet with the batch of cardinals recently promoted by Callixtus II, who were mainly French or Burgundian.

With Callixtus II ’ s death on 13 December 1124, both families agreed that the election of the next pope should be in three days time, in accordance with the church canons.