Adoptionism, closely associated with dynamic monarchianism, is an early Christian nontrinitarian theological doctrine, subsequently revived in various forms. Adoptionism is a theology about relationship, which does not affirm the virgin birth and holds that Jesus was adopted as the Son of God at his baptism, his resurrection, or his ascension. Dynamic Monarchianism does not hold Jesus’ sonship was through adoption. Dynamic monarchianism is a theology about divinity, and holds there is one God, the Father, and Jesus was a man, born of virgin birth, empowered by God’s own divinity through the Holy Spirit, and raised to unity with God, but not a pre-existent distinct divine person. How common adoptionist views were among early Christians is debated, but it appears to have been most popular in the first, second, and third centuries. Some scholars see adoptionism as the belief of the earliest followers of Jesus, based on the epistles of Paul and other early literature. However, adoptionist views sharply declined in prominence in the fourth and fifth centuries, as Church leaders condemned it as a heresy.
Gaston (2023) defines a distinction between adoptionism and dynamic monarchianism as different christologies, while being commonly conflated. Adoptionism refers to a theological position about the relationship between Jesus and the Father (I.e. that he was adopted by God), not the deity of Jesus, while Dynamic Monarchianism is a Christological position about the deity of Jesus. In Dynamic Monarchiansim, “Dynamic” refers to being empowered by the Holy Spirit, while “Monarchianism” emphasizes a single deity (i.e. the Father). Gaston writes that Dynamic Monarchianism describes a Christology that was among the earliest Christologies, held by independent Theologians and maintained within mainstream Christianity until the fourth Century. Dynamic Monarchianism held that Jesus was a miraculously conceived man who, after his resurrection, ascended to heaven and to divine authority, as opposed to being an eternal divine Person who became human. Monarchianism is in contrast to Logos christologies of the second and third century, which distinguish the Logos as another divine person distinct from the Father. Monarchianism is categorized as Modalistic (where Father and Son are different designations for the same person) or Dynamic (where only the Father is God, and Jesus was empowered by his Spirit.