Wikipedia
Adoptivi
The Adoptivi, or Adoptiani, were a medieval religious sect whose name comes from the manner in which they understood Jesus to be the son of God in Christianity.
The Adoptivi base their theology on two Spanish bishops, Felix of Urgel and Elipand of Toledo. Elipand, writing to Felix for an account of his faith where the relationship of Jesus to God is concerned, was answered that, according to the use of the language in respect to Jesus' nature, Jesus was not the natural but adoptive son of God.
Both Elipand and Felix propagated this view towards the close of the 8th century. Both were charged, convicted, and condemned as heretics, and eventually renounced these views.