of the church. There had already been some local councils
at which the bishops and priests of a single province had been
present. For the first time, in 324,[175] Constantine convoked a
General Assembly of the World (an ecumenical council) at Nicaea, in
Asia Minor; 318 ecclesiastics were in attendance. They discussed
questions of theology and drew up the Nicene Creed, the Catholic
confession of faith. Then the emperor wrote to all the churches,
bidding them "conform to the will of God as expressed by the council."
This was the first ecumenical council, and there were three
others[176] of these before the arrival of the barbarians made an
assembly of the whole church impossible. The decisions reached by
these councils had the force of law for all Christians: the decisions
are called Canons[177] (rules). The collection of these regulations
constitutes the Canon Law.

=The Heretics.=--From the second century there were among the
Christians heretics who professed opinions contrary to those of the
majority of the church. Often the bishops of a country assembled to
pronounce the new teaching as false, to compel the author to abjure,
and, if he refused, to separate him from the communion of Christians.
But frequently the author of the heresy had partisans convinced of the
truth of his teaching who would not submit and continued to profess
the condemned opinions. This was the cause of hatred and violent
strife between them and the faithful who were attached to the creed of
the church (the orthodox). As long as the Christians were weak and
persecuted by the state, they fought among themselves only with words
and with books; but when all society was Christian, the contests
against the heretics turned into persecutions, and sometimes into
civil wars.

Almost all of the heresies of this time arose among the Greeks of Asia
or Egypt, peoples who were subtle, sophistical, and disputatious. The
heresies were usually attempts to explain the mysteries of the Trinity
and of the Incarnation. The most significant of these heresies was
that of Arius; he taught that Christ was created by God the Father and
was not equal to him. The Council of Nicaea condemned this view, but
his doctrine, called Arianism, spread throughout the East. From that
time for two centuries Catholics and Arians fought to see who should
have the supremacy in the church; the stronger party anathematized,
exiled, imprisoned, and sometimes killed the chiefs of the oppos