Awesome, I have a question for you. Did the earliest church know that they were called to die for the Messiah? When we become Christians, are we not supposed to take up the cross? Is that not a foundational principle of the true church?
I do not know about the earliest church, but there were some martyrs living in the first century AD who were not willing to give up their faith when they faced death. The inside frieze of St. Peter's Basillica lists the names of such martyrs. Most probably died at Nero's Circus; the Colliseum had not been built when the very earliest martyrs died. It was not until the very end of the first century AD, under the reign of Dalmatian that some MAY have been crucified in the Colliseum.
The Bible was not collated and accepted as the Word of God until the third century AD. It was not a single agreed upon book until Emperor Constantine made the east and west wings of the church come up with one canon. (Previously they differed by 2 books). Therefore, the earliest church did not have the Bible routinely available as it is today, although there were thousands of letters written by the various bishops.
The earliest Christians were from the low ends of society throughout the Roman Empire. Christians formed a social net by helping out people and in the process converted many low income pagans to Christianity. (Except for Caligula, Nero and Dalmatian, the Emperors of the the first two centuries of Rome were supportive of Christianity. They provided a social net, were good soldiers, paid their taxes, etc., etc., etc.) The fundamental question for these new converts was, "Do you believe that Jesus Christ died to take away your sins?" If they answered yes, then the reply was, "Welcome Aboard!" Christianity was very inclusive in its infancy!
It was not until the second through fourth century AD that the true nature of Jesus and God was fully understood. Many of the heresies of the first five centuries of Christianity had to do with Christ's nature. (Prophet? Separate God? Triune God? Equal to Father? Subservient to Father?) And of course, it was not until much later that the East and West churches split over the filoloque dispute. Filo means son and the issue was whether or not the Holy Spirit descended from just the Father, or from the Father and the Son.
Are we supposed to take up Jesus Cross? Yes! Absolutely! Will new converts understand this? Probably not. Mankind did not understand Christianity for at least 400 years (and still does not fully understand it, I might add). To expect a new convert to be able to "get it" all at once is a bit much to expect. We all have our own pace of learning and our own spiritual growth patterns. Understanding Christ takes a life time and then some. Nonetheless, it is always great to say, "Welcome Aboard" to a fellow confessor.
Have a great day!