BeDuhn (Professor of the Comparative Study of Religions, Northern Arizona University) is a comprehensive and impressively documented scholarly study of Marcion's original compilation of sacred scriptures which differs significantly from what was eventually canonized by the fourth century Nicene Council
at the behest of the Roman Emperor Constantine.
For example, in his "Reply to False Accusations," Menno claimed that the Anabaptists were the true heirs of Christian tradition: The learned ones call us Anabaptists because we baptize upon confession of faith as Christ commanded His disciples to do, and as the holy apostles taught and practiced; also the worthy martyr Cyprian, all of the African bishops; and besides because we with the Nicene Council cannot accept the heretical baptism which is of Antichrist as Christian baptism....
Likewise, Menno stated that the law of Theodosius forbidding rebaptism--which the authorities and reformers applied to the Anabaptists--must also condemn, "Christ Jesus, all the apostles, Cyprian the Martyr, as well as the African Bishops [Council of Carthage, 256-257], the Nicene Council, and also the Apostle Paul." (88) Here Menno appealed to ancient church leaders and two councils to support adult baptism.
Constantius also pursued a theological agenda, the background for which lies in the Trinitarian polemics that took place in the East between the Nicene Council
in 325 and the 350s.
In historical terms, the controversy lasted 726-843, launched by emperors Leo III and son Constantine V, countered by John of Damascus' eloquent defence of iconodulia and the 731 Roman synods of Pope Gregory III, halted by the Second Nicene Council
(787) and the empress Irene (797), renewed by Leo V and Theophilus, at whose death Iconoclasm was finally quashed.
Constantinople included more detail about the Holy Spirit, in addition to the Father and the Son, than did the Nicene council
Peter--even though Peter was not Rome's first bishop, there wasn't even a bishop in Rome for the first 100 years after Jesus' death and the concept of a pope as we know it didn't exist, according to nineteenth-century Anglican-turned-Catholic-churchman John Henry Cardinal Newman, until the Nicene Council
of the fourth century.
His own use was too tentative to anticipate the later orthodoxy, yet venturesome enough to be thought heretical before the Nicene Council
. The analogical usage of the predicate homoousios was forgotten, and its literal application to the Godhead was resisted by his followers in his native Alexandria, no less than in his adopted Caesarea.(51)
Heresy (a very loaded word) belongs more to the times of the first and second Nicene councils
than to this day and age.