Millerism
The Millerites were the followers of the teachings of William Miller, who in 1833 first shared publicly his belief that the Second Advent of Jesus Christ would occur in roughly the year 1843.
Origins
Miller was a prosperous farmer, a Baptist lay preacher and student of the Bible, living in northern New York, in the region of that state which has come to be known as the Burned-over district.
Miller spent years of intensive study of symbolic meaning of the prophecies of Daniel, especially Daniel 8:14 (Unto two thousand and three hundred days; then shall the sanctuary be cleansed), the 2300 day prophecy. Miller believed that the cleansing of the sanctuary represented the Earth's destruction by fire at Christ's Second Coming. Using the year-day method of prophetic interpretation, Miller became convinced that the 2,300 day period started in 457 B.C. with the decree to rebuild Jerusalem by Artaxerxes I of Persia. Simple calculation then indicated that this period would end about 1843. In September 1822, Miller formally stated his conclusions in a twenty-point document, including article 15, "I believe that the second coming of Jesus Christ is near, even at the door, even within twenty-one years,—on or before 1843." This document however, remained private for many years.