Wikipedia
Elipando (717 - 808?) named Elipandus in some sources was a Spanish archbishop of Toledo and theologian. He was one of the founders of the Adoptivi sect.
Although he affirmed Catholic teaching that Jesus is true Son of God, eternally begotten from God the Father and thus of one divine nature with the Father, he also proposed that Jesus, as the son of David, according to his human nature was the adopted rather than the natural son of God. Elipando's assertion seemed to suggest that Christ's human nature existed separately from His divine personhood. Thus, it seemed to be a nuanced form of Nestorianism and came to be known as Adoptionism. However, Elipando's Adoptionism was not the same as another ancient heresy also called Adoptionism.
Elipando's teaching was condemned as heresy by the Councils of Ratisbon in 792 and of Frankfurt in 794. The heresy was rejected by the English theologian Alcuin who wrote, among many other works against adoptionism, a Treatise against Elipandus in four books. Paulinus II of Aquileia also composed a book refuting Elipandus unorthodox teachings for the Council of Frankfort.