You seem very confused.I believe you are referring the definition of the word Ekklesia created to the man-made corporation started in 325CE at Nicea by the Pagan Roman Pontiff, Constantine .
Constantine started nothing. Anyway, he was based in Turkey, not Italy. Why is it that, just as in your theology, that you can't seem to get anything right?
Not Trinitarian? Not Christian. No Nicea? Not Christian. You don't get to make up the rules as you go along.
No Christians prior to Nicea???????????
Constantine had altogether more colourful plans. Having restored the unity of the Empire, and, being in course of major governmental reforms as well as of sponsoring the consolidation of the Christian church, he was well aware that Rome was an unsatisfactory capital. Rome was too far from the frontiers, and hence from the armies and the Imperial courts, and it offered an undesirable playground for disaffected politicians. Yet it had been the capital of the state for over a thousand years, and it might have seemed unthinkable to suggest that the capital be moved to a different location. Nevertheless, he identified the site of Byzantium as the right place: a place where an emperor could sit, readily defended, with easy access to the Danube or the Euphrates frontiers, his court supplied from the rich gardens and sophisticated workshops of Roman Asia, his treasuries filled by the wealthiest provinces of the Empire. In the reign of Constantine, 325, the celebrated First Council of Nicaea was held there against the Arian heresy, and the prelates there defined more clearly the concept of the Trinity and drew up the Nicene Creed. The doctrine of the Trinity was finalized at the Council of Constantinople in 381 AD which expressly included the Holy Ghost as equal to the Father and the Son. Constantine had invited all 1800 bishops of the Christian church (about 1000 in the east and 800 in the west), but a smaller and unknown number attended. Eusebius of Caesarea counted 220,[18] Athanasius of Alexandria counted 318,[19] and Eustathius of Antioch counted 270[20] (all three were present at the council). Later, Socrates Scholasticus recorded more than 300,[21] and Evagrius,[22] Hilary of Poitiers,[23] Jerome[24] and Rufinus recorded 318. There seems to be a large chunk of history
shalom b'SHEM Yah'shua HaMashiach
that you seem blazingly ignorant of. The city was originally founded as a Greek colony under the name of Byzantium in the 7th century BC. It took on the name of Konstantinoupolis ("city of Constantine", Constantinople) after its re-foundation under Roman emperor Constantine I, who designated it as his new Roman capital.
Constantine the Roman Pontiff moved the capital of the Roman Empire from Rome to a new city named after himself. It took over five years to construct; while it was under construction, Constantine the Roman Pontiff held court at Nicea.
This is when he invited 1800 bishops to come to his court to re-define "Roman christianity", however only 200 or 300 showed up.