Development of the early church.

Christianity developed in a world of highly syncretistic religion; Alexander the Great and thereby Hellenic culture had overrun much of the civilized Near Eastern world and influenced many local religions. Despite this milieu, mystery religions weren't to become popular in what would become known as the province of Judaea. There are parallels to be observed, however, between how early orthodox Christianity developed and aspects of gnostic mystery religions.

Platonic philosophy told of The Form of the Good, also known as "Plato's god," that could be used to explain deeper levels of dualistic thinking (the inner mystery). The idea of religious narratives as literal truth could be discounted in this process. A variety of other esoteric stories were syncretised from pre-existing mythologies about vegetative/fertility deities, reinterpreting an original tale of a pagan deity to one allegorically symbolizing the awakening of knowledge (gnosis) and the abandonment of an initiate's prior life.

This interpretation of religion was spread throughout the Hellenic sphere of influence, meeting with similar themes from Persian gnosticism. These mystery religions could absorb earlier religions (at least among the literate), the central figure in the mystery could be interchangeable thereby; Egypt had Osiris, in Rome, Bacchus, in Greece, Dionysus, in Phrygia (western Anatolia) Attis, and in Samaria, Antiochus, etc. They all could become metaphors for dualistic esoteric and even occult thought processes beyond their original function. Because of broad similarities between the original figures, some observers have classed them collectively as life-death-rebirth deities.

Despite being surrounded by, trading with and eventually being conquered by cultures with both vegetative/fertility and, later, gnostic/mystery religions, Judaism tended to remain distinct over time in the face of political and cultural pressures. Some scholars, such as George Mendenhall from the University of Michigan and Gary Herion from New York's Hartwick College, theorize that the original teachings of Moses and the prophets were a reaction against the surrounding pagan religions of Egypt and the Near East, and this distinction is what allowed them to survive being absorbed completely into the mainstream of their surrounding environment. Eventually, Gnostic Christianity and Manichaeanism evolved as later, obvious, syntheses of gnosticism and Judeo-Christianity.

Many early vegetative/fertility and later gnostic/mystery religions had similar outward manifestations, some resemble those of Christianity. At the core of most of the mystery religions was the idea of a god born as man from a human mother but with a god as father, so as to represent both the earthly part of mankind and the spiritual part of a divinity merged. The subject goes on to die, for the sins of man or as a representative of the seasonal vegetative cycle, enters the underworld, and is restored to life.

Followers of some mystery religions had a ritual bath or cleansing (in some locations by full immersion in water), and considered themselves afterwards to have been reborn. The early Christian church father Tertullian commented that in certain Mysteries it is by baptism that members are initiated and they imagine that the result of this baptism is regeneration and the remission of the penalties of their sins.

Another religious practice similar to Christianity was the symbolic re-enactment of the death of their god, in many areas using bread and wine to symbolize the body and the blood; this was partly chosen due to the original vegetative nature of the gods (for example, Dionysus was originally associated with grapes) or, because of an ancient Near Eastern political covenant ritual. One surviving inscription regarding this (and explicitly referring to a form of Osiris-Dionysus) states that "he who will not eat of my body and drink of my blood, so that he shall be made one with me and I with him, the same shall not know salvation".

In Euripides' play The Bacchae, Dionysus founds a new religion, and is plotted against by the king, Pentheus; he is arrested, unjustly found guilty, and executed wearing a crown of ivy (which was standard garb for Dionysus), which bears some similarity to tales of Jesus' death. This play was a satire on the relationship between the mystery religions (one devoted to Dionysus and another to Demeter) and the priests of other faiths. Stories and images of Dionysus, for example, Aristophanes' The Frogs, depict him riding on a donkey (one of the animals Dionysus was particularly identified with) on the way to his death, with the crowd waving branches towards him (an ancient practise for welcoming important figures—in Jerusalem it was often done with readily available palms).

Dionysus was also associated with certain trees, and consequently some versions of the myth have him being crucified on one, as attested by various images of various of the manifestations being crucified. Images from other mystery religions also feature crucifixion. One early second century image of crucifixion survives as a wall graffito in Rome, and most scholars so far have considered it depicts Jesus, although it does not specify the identity, and the crucified figure has a donkey's head, an animal associated with Dionysus (although the image is thought to be satire).

Mystery religions also taught that the central figure will return at the end of the world to judge mankind (living and dead); however, this was understood to have the deeper meaning that mankind's fate lay in its own hands and failing to listen to the lessons of the mystery religions would lead to disaster. Similar themes are found in the texts of the Bible, especially in the books of Deuteronomy ("Blessings and Curses") and Exodus (the "Covenant Code") as well as the Beatitudes ascribed to Jesus. Echoes of this are also found in the Hindu and Buddhist concept of karma.

Other parallels exist in stories about Jesus, for example, according to Tacitus, Dionysus was thought to have turned water into wine at a marriage, (a story related to his status as a wine god). Another nativity parallel is that of Dionysus himself being born in a cave, in the presence of three shepherds, which, although seeming at odds with modern interpretations placing the birth of Jesus in a stable, was the original understanding of Christians - the Greek text only specifying a manger and in Bethlehem stables were often housed in caves.

Worship of Mithras (known as Mithraism) developed in the Roman army during the first century BC, though it is currently unknown how this particular mystery religion originated, as it appears to have little to do with the Zoroastrian Mithra. Since it developed amongst a group of highly mobile people (professional soldiers), it quickly spread to the outer regions of the empire. It soon proved to be amongst the most popular of the mystery religions, and at Rome, by the start of the third century emperors were openly encouraging it, as the religion favoured their rule.

One of the ancient gods associated with Mithra was Ea, the moon god, and god of the waters. Ea was referred to as Oannes (or sometimes considered as Oannes' father), which resembles the Greek word Ioannes (i.e. John). According to the myths, Oannes spent the days teaching mankind wisdom. Consequently Ea was thought by Joseph Campbell to be the origin of the story of John the Baptist.

Jesus allegedly was born on the winter solstice (when the sun starts to reappear), six months after John was born on the summer solstice (when the sun starts to disappear); John baptises with water (the symbol of Ea) and Jesus with fire (the symbol of the sun); and Jesus is born to a young virgin whereas John is born to an old married woman. These comparisons, together with the biblical passage where John says to Jesus "as you become more, I must become less", lead Campbell to think that John is used in the story as a representation of the moon, and Jesus as the sun.

By the end of the 3rd century, the popular cults of Apollo and Mithras had started to merge into the syncretism known as Mithras Sol Invictus or simply Sol Invictus (the unconquerable sun—a term also used by other cults), and in 274 the emperor Aurelian (whose mother had been a priestess of the sun) made worship of this form official.

The Emperor Constantine I was, like emperors before him, high priest of the Mithraic religion. However, he was also interested in creating unity for the sake of ease of governance, and to this end involved himself in a dispute between Christian groups over Arianism, summoning the First Council of Nicaea. Constantine mitigated some differences between Christianity and its main competitor, the official religion of Sol Invictus. In doing so, he moved the date of celebration of Jesus' birth to December 25th (since this was the date that Mithras' birth was celebrated, and that of Bacchus (another form of Osiris-Dionysus) as well that of other winter solstice festivals such as Saturnalia).

Popular legend holds that Constantine I was Christian; however, he never publicly recanted his position as high priest of Mithras Sol Invictus, and the only alleged occurrence of Constantine I converting was on his deathbed (as reported by later Church Fathers), which is impossible to verify. However, it was not that unusual for people in the fourth century to avoid fully converting to Christianity until quite late in life, because of the strong warnings against continuing in sin after having converted and the spiritual consequences thereof.

Mainstream Christianity differed from gnostic interpretations of the religion because orthodox Christians took the literal interpretation as the correct one, as would newcomers to the mysteries, thus attracting greater numbers of adherents. This was observed quite early, for example, the second century Celsus (whose words are preserved in Origen's Contra Celsum, a text designed against Celsus) states that Christianity continues to spread amongst the vulgar, nay one can even say it spreads because of its vulgarity, and the illiteracy of its adherents. And while there are a few moderate, reasonable, and intelligent people who are inclined to interpret its beliefs allegorically, yet it thrives in its purer form amongst the ignorant.

Shocked by this development, the emperor Julian (later denoted "the Apostate" because of his departure from Christianity) attempted to restore the previous religion by suppressing and persecuting Christianity, while encouraging both Judaism and a sort of neo-paganism. However, this was short lived, as emperors such as Constantine II repealed Julian's actions and encouraged the growth of Christianity. This state of affairs was finally enforced by a decree in 394 (by Theodosius, an Emperor who ascribed to Christianity) which banned outright any non-Christian worship. After the ban, and subsequent suppression, many Mithraeums were converted into Christian churches (such as Notre-Dame du Taur, and the Church of San Clemente), often dedicated to the archangel Michael.