William Miller was a devout Baptist and careful student of the Bible. In 1818 he calculated a date for the end of the world by using a strictly literal reading of the first chapters of Genesis and other prophetic events in the Bible. He aligned these events with the prophetic numbering systems in the Books of Daniel, Ezekiel, and Revelations. He became convinced that he could use this system to determine the exact period of time between the birth of Jesus, the fall of Jerusalem, and the return of the Messiah. Jesus, Miller predicted, would make his millennial return and the world would end on October 22, 1844. After publishing a book about his theory in 1831, he set off on a speaking tour of the Northeast.

Despite many scoffers and doubters, he steadily gained followers. By 1840 Miller had gathered a sizable following. Most of these "Millerites"— between 50,000 and 100,000 in 1844 — lived in central and eastern Massachusetts. Their religious meetings had all the emotional passion of tent revivals.

As the year of the expected apocalypse neared, believers in the prophecy began to give away their belongings, abandon their crops, and sell their land. In the town of Harvard, one man sold his cows at great sacrifice because there would be no one to care for them when he was "gone up." Women in the Worcester area cut off their hair, removed the ruffles from their dresses, threw or gave away their jewelry, and, in some cases, everything they owned. Others broke up all their furniture declaring that they would no longer have use for tables or chairs or beds. Wanting to be suitably attired for heaven, Millerites made long white garments for themselves that they called their "ascension robes."

In the spring of 1844, a prophetic sign appeared: Miller's prediction that the end of the world was near gained new weight, and new adherents, when a great comet was seen moving across the Massachusetts sky at noontime.

On October 22^nd, believers donned their robes. A large gathering lived in or around Groton. Believing that Christ would return on a mountaintop, they climbed up Mt. Wachusett to await the coming of the Lord. One respectable but arthritic old man from Harvard who could not make it up the mountain stationed himself at the very top of the tallest apple tree in his orchard and waited out the night. In New Bedford, a whole family perched on the branches of an apple tree dressed in their white robes. According to one story, a man accosted Ralph Waldo Emerson and the Reverend Theodore Parker on a Concord road and excitedly asked if they realized that the world was going to end that day. "Mr. Parker said: 'It does not concern me, for I live in Boston.' And Mr. Emerson said: 'The end of the world does not affect me; I can get along without it.'"

The vast majority of Millerites were devastated, and some impoverished, by the failure of the prophecy. A remnant continued to believe. They reinterpreted the meaning of the prophecy and came to see October 22, 1844, as the day of Christ's cleansing of his heavenly, rather than earthly, sanctuary. Today's Seventh-day Adventists carry on Miller's teachings.