To what extent does the council of Nicea reflect the beliefs of the early church?

The council of Nicea was held in A.D. 325 a few hundred years after the early church. Yet it contained church leaders from all over, and it reached a wide consensus on a number of issues. Some of these decisions seem contradictory with Protestantism, specifically the seeming appeal to bishops and the church community as a final authority. For example, the council refers to itself several times as "the great and holy Synod," implying that these decisions are binding to some extent, not just suggestions. It refers to penance, which Protestants typically don't practice. It also heavily implies that church custom ought to be followed: > It has come to the knowledge of the holy and great Synod that, in some > districts and cities, the deacons administer the Eucharist to the > presbyters, whereas **neither canon nor custom permits** that they who > have no right to offer should give the Body of Christ to them that do > offer. And this also has been made known, that certain deacons now > touch the Eucharist even before the bishops. They also state: > It is by all means proper that a bishop should be appointed by all the > bishops in the province which seems to appeal to church consensus in a way that seems to contradict Protestant beliefs. Together, the most clear implication seems to be that believers everywhere are bound to follow the teachings given by ecumenical councils or decisions made by a consensus of bishops. I suppose Protestants could argue that humans are capable of error and that these teachings were a modern invention, not something believed by the early church. But if that were the case, then why would bishops from *all* across the continent be able to agree on these declarations? I'm open to arguments that large swaths of the church had fallen into error by AD 325, or that this contradicts things agreed on in the early church. But I'm not sure how to make that argument. On the one hand, there's a lot here that we don't see said by Ignatius or early writers. On the other hand, I don't see Ignatius *contradicting* what's written here, and a consensus by successors of the apostles could indicate that the apostles themselves did believe these things and passed them on as tradition. Ignatius also writes : > Let no man do anything connected with the Church without the bishop...It is not lawful > without the bishop either to baptize or to celebrate a love-feast That doesn't directly imply everything said at Nicea, but the similarity in what's said at Nicea and by Ignatius seems to strengthen the case that Nicea was based on tradition passed down from the apostles. Why would the tradition change so much and so broadly?