Millennium, << muh LEHN ee uhm, >> in religion, has traditionally been used to refer to a 1,000-year period in which holiness will prevail throughout the world. The period is mentioned in the New Testament Book of Revelation (20:1-6).
Some people have interpreted the passage in Revelation as meaning that Christ will reign on the earth either before or after the 1,000-year period. These views are known as premillennialism and postmillennialism.
Because the Book of Revelation frequently uses numbers symbolically, other people have interpreted this passage spiritually. They regard the millennium as the long period between Christ’s first coming and His second coming. Saint Augustine was the first to set forth this view, known as amillennialism. It is expressed in his book The City of God.