The three principle founders were James White, Joseph Bates, and Ellen White. Other influential pioneers included John Nevins Andrews, John Byington, O. R. L. Crosier, Hiram Edson, John Norton Loughborough, Stephen N. Haskell, and Uriah Smith.
They were staunch anti-trinitarians, many of whom came from The Christian Connexion—a heretical Unitarian, restorationist, Arian and semi-Arian group.
Speaking on the Connexion and their influence on the development of Seventh-Day Adventism, SDA historian George R. Knight writes:
One branch of the Restorationist movement had special importance to Seventh-Day Adventists: the Christian Connexion. James White and Joseph Bates (two of Adventism’s three founders) were members of the Christian Connexion. Beyond that, Joshua V. Himes (the second most influential Millerite leader) was also a Connexionist minister.
All in all, the Christian Connexion made an extremely large impact on both Millerite Adventism and later Sabbatarian Adventism. Beyond general thinking patterns, two examples will have to suffice. The first is that [Joseph] Bates, the apostle of the Sabbath, would frame the seventh-day Sabbath as one of the things needed to be restored to the church before Christ could return (SDA [1847], 60). A second is that Bates and [James] White brought anti-trinitarianism into Adventism from their Restorationist background. Certain Restorationists pointed out that the Bible nowhere uses the word “trinity.” They eventually came to regard the Trinity as one of those doctrines Christianity adopted during the Middle Ages as a product of the “great apostasy” from scripture.
George R. Knight, A Search for Identity: The Development of Seventh-day Adventist Beliefs, pg. 31-2
