Marcion, a native of Sinope in Pontus and a devoted Christian, had immigrated to Rome around 140 and attached himself to the church there.

Associating in Rome with the Syrian Gnostic, Cerdo, Marcion had developed unorthodox perspectives that soon brought him into conflict with the Roman church.

Arguing that the Christian God of love could not have also been the Creator God of the Old Testament, Marcion had maintained that Judaizing tendencies among the earliest disciples have corrupted the original gospel of Jesus and that the Old Testament holds no validity for Christians.

The only one to have correctly understood the original teachings of Jesus, claims Marcion, was Paul.

Rejecting the gospels of Matthew, Mark, and John, he collects ten of Paul's letters and an edited “Gospel According to Luke,” from which he removes all legalistic and Old Testament references; he claims that these documents constitute the rule or canon of the church's teaching.

The Christian church in Rome, compelled to define what it accepts as the true canon, excommunicates Marcion in about 144 and begins assembling the New Testament canon (the version accepted today, inclusive of all four gospels).

Marcion’s substantial following grows rapidly into a sect, based mainly on the premise that the gospel of Jesus Christ is entirely a gospel of love to the exclusion of the Mosaic Law.

Mediterranean Southwest Europe (148–159 CE): Religious Debates and Roman Authority

The era 148–159 CE in Mediterranean Southwest Europe is notable for important religious developments and early indications of Rome's central role in Christian doctrinal discussions. This period highlights interactions between prominent early Christian figures and significant religious controversies.

Polycarp's Visit to Rome and the Paschal Controversy

During the pontificate of Pope Anicetus, the aged Polycarp of Smyrna, a disciple of John the Evangelist, visits Rome to discuss the celebration of Passover. Polycarp and the Church of Smyrna celebrate the crucifixion on the fourteenth day of Nisan, coinciding with the Jewish Passover, regardless of the weekday. In contrast, the Roman Church celebrates Pasch (Easter) on Sunday, commemorating Jesus' resurrection.

Although Polycarp and Anicetus fail to reach an agreement on a unified date for the celebration, Anicetus permits Polycarp and his church to maintain their traditional observance. This divergence initiates the Paschal controversy, which intensifies in subsequent centuries.

Visits by Hegesippus and Early Significance of the Roman See

The historian Hegesippus also visits Rome during Anicetus’s pontificate, reflecting the increasing prominence and importance of the Roman See in early Christian communities. This visit underscores the Roman Church's emerging role as a focal point of doctrinal and ecclesiastical authority.

Anicetus's Opposition to Heresies

Pope Anicetus actively opposes emerging religious movements perceived as heretical, notably Montanism, Gnosticism, and Marcionism. He becomes the first Roman bishop documented to explicitly condemn such teachings, reinforcing the doctrinal authority of Rome and setting precedents for ecclesiastical orthodoxy.

Additionally, Anicetus issues specific regulations, such as decreeing that priests must not have long hair—a measure possibly intended to distinguish orthodox clergy from Gnostic practitioners, known for wearing their hair long.

Continued Economic Prosperity and Provincial Integration

Under Antoninus Pius, Mediterranean Southwest Europe maintains its robust economic growth, with Iberia continuing to be a key provider of exports such as gold, wool, olive oil, and wine. Sustained provincial integration contributes significantly to the region's ongoing prosperity.

Infrastructure and Urban Development

Antoninus Pius continues emphasizing infrastructure projects and urban improvements, enhancing connectivity, trade, and public amenities. These efforts further solidify the empire’s economic and administrative efficiency, benefiting both urban and rural populations.

Cultural and Intellectual Vibrancy

Cultural and intellectual life continues to thrive, supported by Antoninus’s patronage. Literary, philosophical, and scientific endeavors flourish, maintaining Rome’s sophisticated intellectual traditions and scientific inquiries.

Legacy of the Era

The era 148–159 CE is marked by significant religious debates, emphasizing Rome’s emerging role as a center of ecclesiastical authority and doctrinal definition. Coupled with sustained economic prosperity and cultural vibrancy, these developments profoundly shape the trajectory of Mediterranean Southwest Europe, influencing religious, social, and cultural dynamics for generations to come.

The aged Polycarp of Smyrna, a disciple of John the Evangelist, visited Rome to discuss the celebration of Passover with Pope Anicetus, according to Irenaeus.

Polycarp and his Church of Smyrna celebrate the crucifixion on the fourteenth day of Nisan, which coincides with Pesach (or Passover) regardless of which day of the week upon this date falls, while the Roman Church celebrates the Pasch on Sunday—the weekday of Jesus' resurrection.

The two do not agree on a common date, but Anicetus concedes to Polycarp and the Church of Smyrna the ability to retain the date to which they are accustomed.

The controversy is to grow heated in the following centuries.

The Christian historian Hegesippus also visits Rome during Anicetus' pontificate.

This visit is often cited as a sign of the early importance of the Roman See.

Anicetus is the first Roman Bishop to condemn heresy by forbidding Montanism.

He also actively opposes the Gnostics and Marcionism.

According to Liber Pontificalis, Anicetus decreed that priests are not allowed to have long hair (perhaps because the Gnostics wore long hair).

Mediterranean Southwest Europe (148–159 CE): Religious Debates and Roman Authority

The era 148–159 CE in Mediterranean Southwest Europe is notable for important religious developments and early indications of Rome's central role in Christian doctrinal discussions. This period highlights interactions between prominent early Christian figures and significant religious controversies.

Polycarp's Visit to Rome and the Paschal Controversy

During the pontificate of Pope Anicetus, the aged Polycarp of Smyrna, a disciple of John the Evangelist, visits Rome to discuss the celebration of Passover. Polycarp and the Church of Smyrna celebrate the crucifixion on the fourteenth day of Nisan, coinciding with the Jewish Passover, regardless of the weekday. In contrast, the Roman Church celebrates Pasch (Easter) on Sunday, commemorating Jesus' resurrection.

Although Polycarp and Anicetus fail to reach an agreement on a unified date for the celebration, Anicetus permits Polycarp and his church to maintain their traditional observance. This divergence initiates the Paschal controversy, which intensifies in subsequent centuries.

Visits by Hegesippus and Early Significance of the Roman See

The historian Hegesippus also visits Rome during Anicetus’s pontificate, reflecting the increasing prominence and importance of the Roman See in early Christian communities. This visit underscores the Roman Church's emerging role as a focal point of doctrinal and ecclesiastical authority.

Anicetus's Opposition to Heresies

Pope Anicetus actively opposes emerging religious movements perceived as heretical, notably Montanism, Gnosticism, and Marcionism. He becomes the first Roman bishop documented to explicitly condemn such teachings, reinforcing the doctrinal authority of Rome and setting precedents for ecclesiastical orthodoxy.

Additionally, Anicetus issues specific regulations, such as decreeing that priests must not have long hair—a measure possibly intended to distinguish orthodox clergy from Gnostic practitioners, known for wearing their hair long.

Continued Economic Prosperity and Provincial Integration

Under Antoninus Pius, Mediterranean Southwest Europe maintains its robust economic growth, with Iberia continuing to be a key provider of exports such as gold, wool, olive oil, and wine. Sustained provincial integration contributes significantly to the region's ongoing prosperity.

Infrastructure and Urban Development

Antoninus Pius continues emphasizing infrastructure projects and urban improvements, enhancing connectivity, trade, and public amenities. These efforts further solidify the empire’s economic and administrative efficiency, benefiting both urban and rural populations.

Cultural and Intellectual Vibrancy

Cultural and intellectual life continues to thrive, supported by Antoninus’s patronage. Literary, philosophical, and scientific endeavors flourish, maintaining Rome’s sophisticated intellectual traditions and scientific inquiries.

Legacy of the Era

The era 148–159 CE is marked by significant religious debates, emphasizing Rome’s emerging role as a center of ecclesiastical authority and doctrinal definition. Coupled with sustained economic prosperity and cultural vibrancy, these developments profoundly shape the trajectory of Mediterranean Southwest Europe, influencing religious, social, and cultural dynamics for generations to come.

The cosmopolitan hospitality to eastern religions may have allowed the first attested Christian community in Gaul to be established in Lugdunum in the second century, led by a bishop with the eastern name of Pothinus.

In 177 it also becomes the first in Gaul to suffer persecution and martyrdom.

The event is described in a letter from the Christians in Lugdunum to counterparts in Asia, later retrieved and preserved by Eusebius.

There is no record of a cause or a triggering event but mob violence against the Christians in the streets culminates in a public interrogation in the forum by the tribune and town magistrates.

The Christians publicly confess their faith and are imprisoned until the arrival of Legate of Lugdonensis, who gives his authority to the persecution.

About forty of the Christians are martyred—dying in prison, beheaded, or killed by beasts in the arena as a public spectacle.

Among the latter are Bishop Pothinus, Blandina, Doctor Attalus, Ponticus, and the deacon Sanctus of Vienne.

Their ashes are thrown into the Rhône.

Nevertheless, the Christian community either survives or is reconstituted, and under Bishop Irenaeus it continued to grow in size and influence.

The Montanist movement, which originated in Asia Minor, has made its way to Rome and Gaul in the second half of the second century, around the reign of Eleuterus.

Its nature does not diverge so much from the orthodoxy of the time for it to initially be labeled heresy.

During the violent persecution at Lyon, in 177, local confessors had written from their prison concerning the new movement to the Asiatic and Phrygian communities, and also to Pope Eleuterus.

The bearer of their letter to the pope is the presbyter Irenaeus, soon to become Bishop of Lyon.

It appears from statements of Eusebius concerning these letters that the Christians of Lyon, though opposed to the Montanist movement, advocated patience and pleaded for the preservation of ecclesiastical unity.

Exactly when the Roman Catholic Church takes its definite stand against Montanism is not known with any certainty.

It would seem from Tertullian's account (adv. Praxeam, I) that a Roman bishop did send some conciliatory letters to the Montanists, but these letters, says Tertullian, were subsequently recalled.

He probably refers to Pope Eleuterus, who long hesitated, but after a conscientious and thorough study of the situation, is supposed to have declared against the Montanists.

At Rome, the Gnostics and Marcionites continue to preach against the orthodox church.

The Liber Pontificalis ascribes to Pope Eleutherius a decree that no kind of food should be despised by Christians (Et hoc iterum firmavit ut nulla esca a Christianis repudiaretur, maxime fidelibus, quod Deus creavit, quæ tamen rationalis et humana est).

Possibly he did issue such an edict against the Gnostics and Montanists; it is also possible that on his own responsibility, the writer of the Liber Pontificalis attributed to this pope a similar decree current about the year 500.

Irenaeus, Bishop of Lugdunum in Gaul, writes a five-volume work in the second century, On the Detection and Overthrow of the So-Called Gnosis, today also called On the Detection and Overthrow of Knowledge Falsely So Called (Greek: lit. "Elenchus and Overturning of the Pseudonymous Knowledge"), commonly called Against Heresies (Latin: Adversus haereses).

The final phrase "of knowledge falsely so-called" (Greek: tes pseudonymou gnoseos genitive case; or nominative case pseudonymos gnosis) is a quotation of the apostle Paul's warning against "knowledge falsely so-called" in 1 Timothy 6:20.

Due to its reference to Eleutherus as the current bishop of Rome, the work is usually dated to about 180.

In it, Irenaeus identifies and describes several schools of gnosticism and contrasts their beliefs with what he describes as catholic, orthodox Christianity.

Only fragments of the original Greek text exist, but a complete copy exists in a wooden Latin translation, made shortly after its publication in Greek, and Books IV and V are also present in a literal Armenian translation.

Irenaeus’s purpose in writing Against Heresies is to refute the teachings of various Gnostic groups; apparently, several Greek merchants had begun an oratorial campaign praising the pursuit of "gnosis" in Irenaeus' bishopric.

Another popular theory states that a group of Gnostics known as the Valentinians remained part of the early Christian church, taking part in regular church celebrations despite their radical differences.

It is also said that Gnostics would secretly meet outside of regular church activity where they would discuss their "secret knowledge" and scripture that pertains to it.

As bishop, Irenaeus felt obligated to keep a close eye on the Valentinians and to safeguard the church from them.

In order to fulfill this duty, Irenaeus educated himself and became well informed of Gnostic doctrines and traditions.

This eventually led to the compilation of his treatise.

It appears however, that the main reason Irenaeus had taken on this work was because he felt that Christians in Asia and Phrygia especially need his protection from Gnostics, for they do not have as many bishops to oversee and help keep problems like this under control (probably only one bishop was assigned to a number of communities).

Therefore, due to the issue of distance between Irenaeus (who is in the western Roman province of Gaul) and the orthodox Christian community of Asia, Irenaeus finds that writing this treatise will be the best way to offer them guidance.

Against Heresies was the best surviving contemporary description of Gnosticism until the discovery of the Library of Nag Hammadi in 1945.

This publication is historically important as the dating of the publication is irrefutable and the document is among the earliest non-controversial confirming documentation for many of the sayings attributed by early Christian writers to Jesus and to the Letters of Paul.

Bardaisan is forced at the age of sixty-three to take refuge in the fortress of Ani in Armenia, where he tries to spread the Gospel, but with little success.

He will die five years later, either at Ani or at Edessa.

Bardaisan apparently was a voluminous author, and though nearly all his works have perished, we find notices of the following: • Dialogues against Marcion and Valentinus.

• Dialogue "Against Fate" addressed to an Antoninus.

Whether this Antoninus is merely a friend of Bardaisan or a Roman emperor and, in the latter case, which of the Antonini is meant, is matter of controversy.

It is also uncertain whether this dialogue is identical with "The Book of the Laws of the Countries".

• A "Book of Psalms", one hundred and fifty in number, in imitation of David's Psalter.

These psalms will become famous in the history of Edessa, their words and melodies living for generations on the lips of the people.

Only when St. Ephrem composes hymns in the same pentasyllabic meter and has them sung to the same tunes as the psalms of Bardaisan, will the latter gradually lose favor.

• Astrologico-theological treatises, in which his peculiar tenets were expounded.

• A "History of Armenia", a history of the Armenian kings.

• "An Account of India".

Bardaisan obtained his information from the Indian Sramana (wandering monks) ambassadors to the Roman Emperor Heliogabalus.

A few extracts are preserved by Porphyry and Stobaeus.

• "Book of the Laws of the Countries".

Against a questioning disciple called Abida, Bardaisan seeks to show that man's actions are not entirely necessitated by Fate, as the outcome of stellar combinations.

From the fact that the same laws, customs and manners often prevail among all persons living in a certain district, or though locally scattered living under the same traditions, Bardaisan endeavors to show that the position of the stars at the birth of individuals can have but little to do with their subsequent conduct, hence the title "Book of the Laws of the Countries."

Theodoret, bishop of Cyrrhus (Syria) from 423, has converted more than one thousand Marcionites in his diocese.

The Middle East: 664–675 CE

The Rise of Paulicianism and Continued Umayyad Consolidation

Emergence of the Paulicians

In Armenia, between 664 and 675 CE, a Christian dualist group known as the Paulicians emerges, significantly influenced by earlier dualist movements such as Marcionism and Manichaeism. The Paulicians advocate a fundamental dualism, believing in two opposing principles: an evil God who creates and governs the material world, and a good God who presides over the spiritual world to come. Consequently, they reject the idea that Jesus could have been the true son of Mary, as such an incarnation would contradict their belief in the purity of the spiritual deity.

Doctrinal Distinctiveness and Rejection of Orthodoxy

Paulician teachings emphasize the Gospel According to Luke and the Letters of St. Paul, while explicitly rejecting the Old Testament and the Letters of St. Peter. Their repudiation extends to the established Church’s sacraments, rituals, hierarchy, and clergy. This radical stance challenges both religious orthodoxy and established ecclesiastical authority, positioning the Paulicians in direct conflict with mainstream Christianity.

Constantine of Mananali and the Founding of Kibossa

The sect’s probable founder, Constantine of Mananali, hailed from the region near Samosata, Syria. Adopting the additional name Silvanus—after Silas, a companion of St. Paul—Constantine reshapes the prevalent Manichaean beliefs into a distinctly Christian dualist theology. He becomes renowned as a teacher and establishes a significant Paulician community at Kibossa near Colonia in Armenia. Under his leadership, the Paulicians grow rapidly, both religiously and politically, initiating rebellions that challenge the authority of Byzantine rule.

Continued Umayyad Strengthening

Parallel to these religious upheavals, the Umayyad Dynasty, recently established in 661 CE, consolidates its political dominance. Under Caliph Muawiya ibn Abi Sufyan, the Umayyads further strengthen central authority from their capital at Damascus, promoting administrative and military reforms that stabilize and expand Islamic rule across the Middle East. This era thus becomes marked by both significant religious dissent, exemplified by the Paulicians, and continued political consolidation under the Umayyads, setting the stage for further transformations in the Middle East.