Adoptionism
Adoptionism says that Jesus was a human being who was "adopted" by God at his conception, at which point he developed a divine nature. Later versions sometimes suggest that he was adopted later, such as when he was baptized by John the Baptist.
Adoptionism refers to two Christian heresies. One was developed in the 2nd and 3rd centuries and is also known as Dynamic Monarchianism. The other began in Spain during the 8th century and was concerned with the teaching of Elipandus, archbishop of Toledo. Wishing to distinguish in Christ the operations of each of his natures, human and divine, Elipandus referred to Christ in his humanity as “adopted son” in contradistinction to Christ in his divinity, who is the Son of God by nature. The son of Mary was not the Son of God by nature but only by adoption.
Opposition to this view of Christ led Pope Adrian I to intervene and condemn the teaching. Elipandus gained the support of Felix, bishop of Urgel, who eventually engaged in a literary duel with Alcuin of York over the doctrine.
In 798 Pope Leo III held a council in Rome that condemned the “Adoptionism” of Felix and anathematized him. Felix was forced to recant in 799 and was placed under surveillance. Elipandus remained unrepentant, however, and continued as archbishop of Toledo, but the Adoptionist view was almost universally abandoned after his death.