The period in which the fourth kingdom exists has a mysterious two thousand year hole in it, that is, from the crucifixion of Jesus to the commencement of the ministries of the Two Witnesses of Revelation chapter eleven, it is as though the prophetic time clock has stopped.
Here the fourth kingdom beast is depicted as an enormous red dragon with seven heads and ten horns. The thing that I would like you to note is that there are seven crowns on his seven heads.