Excerpts from Books and Wikipedia
"In the eighth chapter of the Book of Daniel, verse thirteen, it is said: "Then I heard one saint speaking, and another saint said unto that certain saint which spake, How long shall be the vision concerning the daily sacrifice, and the transgression of desolation, to give both the sanctuary and the host to be trodden under foot?" Then he answered (v. 14): "Unto two thousand and three hundred days; then shall the sanctuary be cleansed"; (v. 17) . . . He appoints two thousand three hundred years, for in the text of the Bible each day is a year. Then from the date of the issuing of the edict of Artaxerxes to rebuild Jerusalem until the day of the birth of Christ there are 456 years, and from the birth of Christ until the day of the manifestation of the Báb there are 1844 years. When you add 456 years to this number it makes 2300 years. That is to say, the fulfillment of the vision of Daniel took place in the year A.D. 1844, and this is the year of the Báb's manifestation according to the actual text of the Book of Daniel. Consider how clearly he determines the year of manifestation; there could be no clearer prophecy for a manifestation than this." See "Daniel."