No one knows the day or hour of the rapture, not even the angels in heaven or Jesus, but only the Father (ref. Matthew 24:36). Three of the more popular theories for when the rapture will take place are (1) pre-tribulation, (2) mid-tribulation, and (3) post-tribulation. The most popular theory amongst Christians is pre-tribulation which claims the rapture will occur just prior to the beginning of the seven-year tribulation period. The mid-tribulation theorists believe the rapture will take place 3 ½ years into the seven-year tribulation period and the post-tribulation theorists believe the rapture will occur at the end of the seven-year tribulation period.