4 Horses of Revelation

I see John’s penning of Christ’s words in Revelation 1:19 (NASB) as the KEY for everything John writes within the boundaries of this book. This is *quoted* to us as **Preceding** (“the things which you have seen”), **Current** (“the things which are”), and **Future** (“the things which will take place after these things”). Were the 4 horses released upon the world in the past?