The Great Disappointment refers to a significant event in the history of the Millerite movement, which was a religious movement in the United States during the 19th century. Followers of William Miller, a Baptist preacher, believed that Christ would return on October 22, 1844. When this did not happen, many of his followers were left disillusioned and confused. The aftermath of the Great Disappointment led to a split among the Millerites. Some members abandoned their beliefs, while others sought to reinterpret the event. This eventually contributed to the formation of the Seventh-day Adventist Church, which emerged from the movement and continues to exist today.