Hi Brian —
That's only because it took a couple of centuries for Christianity to become codified. Until Nicea, we essentially had lots of very different groups calling themselves "Christians".
I do think however, that the idea that Christianity was a disparate collection of varying beliefs without a centre or core until Nicea is, again, another generalisation that does not really reflect the actuality.
It was because of the Emperor Constantine's support of the Church that allowed free and open debate, until then the various centres were subject to imperial censure and sometimes persecution that the Church had to remain largely 'underground'.
There is a significant body of evidence to support the thesis that there was such a core, and a core set of doctrines, evident in the Pauline preaching for example, that indicates a common belief across the empire as it was then known.
The codification of Nicea — the Creed — was itself formulated from catechetical teachings drawn from a number of sources, or centres, of Christian praxis; Jerusalem, Alexandria and Antioch primarily.
The Arian Dispute, for example, began as an authentic pastoral issue, and theological question, but very quickly the theological dimension was sidelined as the main players sought political ascendancy — Arius himself laments this turn of events.
I think that's the point of generalisations.
But they're neither useful nor helpful when not grounded in evidential argument, but rather serve polemical or even prejudicial viewpoints.
The initial premise of this discussion, that 'Ebionite/Nazarene' best characterises the Early Church is a gross generalisation on two points. The first is that it does not allow for the change in character of the groups themselves over time. In Acts Luke refers to 'the Way', but to then assume that this specific 'way' was synonymous with any other 'way', simply by virtue of the designation, is palpably inaccurate.
Likewise the designation of the belief systems of the Ebionites and Nazarenes of the 2nd/3rd century as determining the meaning of the term in the 1st century is also inaccurate. What is evident is that these names came to designate a body of belief that accepted, or did not accept, that body of doctrine designated 'Catholic' (by Ignatius of Antioch in the 1st century) which itself clearly indicates an 'orthodox' doctrine, that was empire-wide, as opposed to those heterodox doctrines which should be examined on their own account.
That the Nazarenes accepted the Virgin Birth for example, whilst the Ebionites didn't, indicates that the Virgin Birth was indeed a doctrine from the earliest times, and furthermore that such groups sought to distance themselves to a greater or lesser degree from what they saw as a central but erroneous teaching.
Rather than just declare such groups orthodox, therefore, let alone principle Christian designations, one needs to examine their doctrines against Liturgical practice and Scriptural teaching.
Are we talking about Mithraism or Christianity? If Christianity, don't you mean Greek theology with Hebrew philosophy?
Well that is a recurring issue, but fundamentally Christianity was a Hebrew monotheism which sought to reason its doctrine by Greek philosophy — but the point remains that the question of the Hellenisation of a Hebrew doctrine. Neither the two principles axes of debate — Christology and the Trinity — would not have emerged as they did from a Hellenic and fundamentally dualist theology. Nor would the Christian idea of the person.
All three ideas, as doctrine: The Triune Godhead, the Incarnation and the sanctification/divinisation of man, were well in place before Nicea, as evidenced by the fact that the dispute was triggered by the lay community in Alexandria, not by theologians, but rather by their rejection of Arius' overtly Platonic interpretation of theology which, in defence of an absolute monotheism, sought to define God as utterly Transcendent at the cost of any possibility of Divine Immanence.
What is most striking to me is that those who most vociferously defend the modern idea of the autonomous (and anti-corporate) spirituality (in all its senses) of the person, champion those movements — Ebionite, Nazarene, Cerinthian, Essene, Gnostic, (in the sense of the 2nd century doctrines), Montanist and later Cathar, etc. — which invariably absolutely refute any idea of a holistic and inhering spirituality whatsoever, let alone the idea of autonomy ...
What continually draws me to Catholicism is a doctrine which is the most optimistic and which opens up the possibility of what an authentic human being can be.
Thomas