Adoptionist

Alfonso's envoys to Charlemagne's courts may have also dealt with the adoptionist controversy, which had brought Bermudo's kingdom into Charlemagne's view.

Despite the shared name of "Adoptionism" the Spanish Adoptionist Christology appears to have differed sharply from the Adoptionism of early Christianity.

In 269, the Synods of Antioch condemned Paul of Samosata for his Adoptionist theology, and also condemned the term homoousios (ὁμοούσιος, "of the same being") in the sense he used it.

In 791, Felix appealed to Charlemagne in defense of the Spanish Adoptionist teaching, sending him a tract outlining it.

Today I have begotten you"; the latter phrase that may show Adoptionist tendencies.