A sect founded by a physician, John Thomas (b.1805), who emigrated to America in 1832, and at first associated with the Campbellites and Millerites. He revisited England three times, and founded ecclesias, of which the dominant one has always been in Birmingham, although there have been several splinter groups. The most influential British leader was Robert Roberts, founder of the journal The Christadelphian and expounder of Christadelphian doctrines in his standard textbook Christendom Astray from the Bible.
Adherents accept the Bible as their sole authority. They reject the immortality of the soul. They are anti-Trinitarian and believe in one personal. They hold that had no existence, except in the mind of the Father, before he was born of the Virgin Mary. Although his body was necessarily “unclean,” he was personally free from sin, and received the resident divinity from the Father through the at his baptism. The Holy Spirit is the name for the power of God in action. There is no personal devil, but Satan is a personification of sin in the flesh. The death of Christ on the cross was not expiatory, but in order “to express the love of the Father in a necessary sacrifice for sin.” Salvation is through perseverance in good works and through acceptance of Christadelphian doctrines and baptism. Christadelphians reject any teaching of “heaven beyond the skies,” but emphasize the promises to Abraham and Israel, and look for the return of Jesus to reign permanently in Jerusalem. The saved will be raised to live in the renewed earth, while the wicked will be annihilated.
They are democratic in organization, and as brethren they have no separate ministry. Each ecclesia is independent, although a member of the wider Christadelphian fellowship. It is estimated there are some 20,000 Christadelphians in Britain and perhaps a similar number in the USA. They spread their views largely by public lectures and Bible exhibitions.
See R. Roberts, Christendom Astray (1862, continually reprinted), and B. Wilson, Sects and Society (1961): the fullest “neutral” account of the movement.