This church was founded on a failed prediction, which it has never concealed and has instead built a doctrine around.
William Miller, a Baptist lay preacher in New York, calculated from the prophecy of Daniel that Christ would return around 1843-44, and the date was eventually fixed on 22 October 1844. Tens of thousands sold property, settled debts and waited. Nothing happened, and the day is known in the movement's own vocabulary as the Great Disappointment.
Most Millerites went home. A small group concluded instead that the date had been right and the event misidentified: that what Daniel described was not Christ's return to earth but his entry into the most holy place of a heavenly sanctuary, beginning an investigative judgment which would precede his coming. This teaching is peculiar to Adventism, has no parallel in other Christian bodies, and has been contested inside the church itself, most sharply by the Adventist scholar Desmond Ford in 1980, whose challenge to it cost him his ministerial credentials.
Two other convictions were added quickly. From Seventh Day Baptist contact came the seventh-day Sabbath, kept from Friday sunset to Saturday sunset, on the ground that the fourth commandment was never repealed or transferred to Sunday. And from Ellen G. White, who began having visions at seventeen, came the counsels that shaped the church's teaching, its health work and its institutional expansion.
The church organised formally in 1863 with a few thousand members. It also holds conditional immortality: the dead sleep unconscious until resurrection, and the lost are finally destroyed rather than tormented for ever, which places Adventists with a minority of Christians on hell and with a very small minority on the state of the dead.