Doctrine: a particular principle, position, or policy taught or advocated, as of a religion or government; a body or system of teachings relating to a particular subject.
If only understanding (and agreeing to) Christian doctrine was so easy….
Matthew 28: 19 Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20(a) teaching them to observe all that I have commanded you.
John 21: 25 Now there are also many other things that Jesus did. Were every one of them to be written, I suppose that the world itself could not contain the books that would be written.
The dating of when the books of the New Testament were written is a bit difficult to nail down. Suffice it to say, even if the earliest dates for each book are utilized, those to whom Jesus gave the Great Commission and the communities they reached would not have had access to these for many years, even decades.
They would have had access to what these disciple-missionaries knew from the oral teaching by and the life of Christ. They would have had knowledge of what the Apostle John mentions – the many other things Jesus did that are not in his book. But they wouldn’t have had the book – or books. No Gospels, no letters, no Sola Scriptura.
Yet we know, even after 2,000 years, that having the books does little to help resolve differences – even by the most honest and sincere and ecumenically-minded theologians.
Where did these first disciples go? Many places, many traditions, many possibilities. By tradition, James went to Spain, Bartholomew went to India and Armenia as did Thomas, Matthew to Ethiopia, Simon and Jude to the Parthian Empire, Matthias to the north shore of the Black Sea, Andrew to Crimea and present-day Ukraine.
All points in-between were also covered by these and others. Of course, different countries and cultures have their own tradition regarding which apostles, etc. They don’t all agree….
As we know, they did not all go together. They also did not have identical memories and understandings; they did not have a common memorized creed. We see even Peter and Paul in disagreement in the book of Acts.
All of this commonality was yet to be developed, the doctrines to be worked out, the creeds to be memorialized.
Why all of this background?
The Council of Chalcedon Re-Examined, by V.C. Samuel
Chalcedon resulted in the first long-lasting (and remaining) split in the Christian Church. Yes, there have been other divides, but some lasted years or decades, maybe even a century or two. But nothing like what happened after Chalcedon. The split gave us what we today know as the Oriental Orthodox Churches – including Ethiopian, Armenian, and Coptic, among a small handful of others.