on of
the Holy Ghost, and the mystery of the Incarnation.

Felix, bishop of Urgel in Catalonia, in a letter to Elipandus, bishop of
Toledo, who had consulted him on that subject, before the year 783,
pretended to prove that Christ as man is not the natural, but only the
adoptive Son of God: which error he had already advanced in his public
discourses.[1] The rising error was vigorously opposed by Beatus, a
priest and abbot, and his disciple Etherius, who was afterwards bishop
of Osma. Soon after it was condemned by a council at Narbonne, in
788,[2] and by another at Ratisbon, in 792, while Charlemagne kept his
court in that city. Felix revoked his error first in this council at
Ratisbon, and afterwards before pope Leo III. at Rome.[3] Yet after his
return into Spain he continued both by letters and discourses to spread
his heresy; which was therefore again condemned in the great council of
Frankfort, in 794, in which a work of our saint, entitled
Sacro-Syllabus, against the same, was approved, and ordered to be sent
into Spain, to serve for all antidote against the spreading poison.[4]
From this book of St. Paulinus it is clear that Elipandus also returned
to the vomit. Alcuin returning from England, where he had stayed three
years, in 793, wrote a tender moving letter to Felix, exhorting him
sincerely to renounce his error. But the unhappy man, in a long answer,
endeavored to establish his heresy so roundly as to fall into downright
Nestorianism, which indeed is a consequence of his erroneous principle.
For Christ as man cannot be called the adoptive Son of God, unless his
human nature subsist by a distinct person from the divine.[5] By an
order of Charlemagne, Alcuin and St. Paulinus solidly confuted the
writings of these two heresiarchs, the former in seven, our saint in
three books. Alcuin wrote four other books against the pestilential
writings of Elipandus, in which he testifies that Felix was then at
Rome, and converted to the Catholic faith. Elipandus, who was not a
subject of Charlemagne, could not be compelled to appear before the
councils held in his dominions, Toledo being at that time subject to the
Moors. Felix, after his relapse, returned to the faith with his
principal followers in the council of Aix-la-Chapelle, in 797.[6] From
that time he concealed his heresy, but continued in secret to defend it,
and at his {286} death, in 815, left a written profession of his
heresy.[7] Elipandus died in 809.[8]