The Seventh-ay Adventist (abbreviated "Adventist") Church is a Protestant Christian denomination which is distinguished mainly by its observance of Saturday, the original seventh day of the Judeo-Christian week, as the Sabbath. The denomination grew out of the Millerite movement in the United States during the middle part of the 19th century and was formally established in 1863. Among its founders was Ellen G. White, whose extensive writings are still held in high regard by the church today.