William Miller (February 15th 1782 - December 20th 1849) was a preacher American Méthodiste . Its message was based on the importance of biblical prophecies.

Of modest origin and veteran of the War of 1812, Miller started to preach in 1831. Basing on Daniel 8-9, he thought that: 2300 years (according to the biblical principle of day-year) would pass between the moment when the order to rebuild the Temple of Jerusalem would be given and moment when Jesus-Christ would return on ground for the second advent.

This order would have been given to the scribe Esdras by the king of Perse Artaxerxès Ier in the seventh year of its reign, i.e. in 457 before J. - C. (see the book of Esdras 7:12 - 26). Thus, 1843 should have been the year of the return of the Christ. As the expiry approached, Miller specified the date with the March 21st 1843. After this date, a study observed that a year ago zero in the calendar georgien, the true date was to thus be the October 22nd 1844.

The not-arrival of Christ in 1844 was named the great disappointment . It is estimated that the Millerites are then approximately 50  000. Several groups will be formed then. Among them, in particular under the impulse of Ellen White, will be born the adventist from the seventh day.

It is in addition discussed because of its membership of freemasonry.