William Miller was born in 1782, in Pittsfield, Massachusetts, and grew up in rural New York state. In 1803, Miller married and moved to Poultney, Vermont where he took up farming. While in Poultney, Miller was elected to a number of civil offices. He was first a Constable, then he was elected to the office of Deputy Sheriff and later was elected Justice of the Peace. Miller served in the Vermont militia and was commissioned a Lieutenant in 1810.
Miller was a soldier in the War of 1812, rising to the rank of Captain. He saw his first major battle at the Battle of Plattsburgh, where vastly outnumbered American forces overcame the British. Miller wrote about his experience and came to view the outcome of this battle as miraculous, and thought that it was a sign that God had a hand in the outcome.
After the war, Miller began to study the Bible extensively, and through his studies became extremely interested in prophecies related to the coming of the Messiah during the Roman Empire, and his 2nd return in the future. Miller took all the numbers mentioned in these prophecies and in other parts of the Bible, and by the year 1818 came up with a calculation of when he believed the Messiah would come again, that year being 1843, although he would not make it public until years later.
Matthew 24: 36
No one knows about that day or hour, not even the angels in heaven, nor the Son, but only the Father.
I think they forgot to read that part.