Were Early Churches Ruled by Elders or a Single Bishop?

There is a never-ending debate amongst theologians and pastors about the proper form of gov­ernment for the church. From the bishop-led Anglicans to the in­formal Brethren churches, there is great diversity. And one of the fundamental flash points in this de­bate is the practice of the early church. What form of government did the earliest Christians have? Were the earliest churches ruled by a plurality of elders or a single bishop?