The fourth kingdom was represented by the legs of Iron in the image of Nebechadnezzer's dream in Dan. The latter phase of the kingdom is represented by the feet or iron and clay. This kingdom is also represented by the terrible beast of Dan. This fourth kingdom was the Roman empire. The son of perdition is called the Anti-Christ and spoken of in Rev. 13 where he makes all who dwell on the earth to receive the mark of the beast.
Sacred history consists of different dispensations or 'economies'.
A dispensation is a period of time during which man is tested in respect of obedience to some specific revelation of the will of God. Dispensational schemes will vary slightly from one author to the next. A new period or dispensation begins when God introduces a change in the principles or ordinances valid up to that time. For example a number of ordinances are introduced at the time of Noah. At the coming of Christ many of the Mosiac Laws or ordinances are annulled.