Who were the "Four Horsemen of the Apocalypse? The fabled backfield of Notre Dame's 1924 football team when Knute Rochne was coach? Yes, that was their nickname. but the original Four Horsemen are described in the the Book of Revelation (or Apocalypse)

In chapter 4 of the Book of Revelation, God is sitting on a Throne in heaven. A scroll is in His hand. It contains "what shall come " in the History of the world. But that scroll is sealed.

The scroll is described in Chapter 5. It is rolled up parchment, sealed along the leading edge 7 times. Before the contents can be known and the present, future and ultimate events of History be revealed, all the 7 seals must be removed. Only the Risen Christ can do that. Only Christ can explain the History of the world. Only He can make known what is to come (Rev 1:1) He has the right do that because He has ransomed the Elect by His Blood and has, by His Resurrection, conquered Sin and Death (5:1-5, 9-10 cf 1:17-18) The Major Truth here is that the Risen Christ holds the Key to understanding the overarching meaning of History. He alone reveals where it is going and how it shall get there. What is the meaning of the 7 seals? As they are opened, they reveal that war, famine, disease, persecution, natural disasters, catastrophes and death shall always be part of the human experience. Christians can not escape these things. We must not see the world through rose colored glasses. We live in a fallen world and can not avoid its evil. But the Book of Revelation hastens to assure us God is on the Throne. The ultimate Kingdom, Power and Glory are His. The primary purpose of the Book of Revelation is to bring comfort and encouragement to the persecuted Church. This is even more relevant in our time as Christians are being oppressed and persecuted around the world in greater numbers than ever before. Currently, 200 million people around the world are suffering because they are Christians. Terrible evil shall not go unanswered by the Sovereign of the Universe. His Name, His reputation, His Glory and Justice are all at stake.
Let us a take a closer look at the first 4 Seals in Rev. 6:1-8

1 Now I watched when the Lamb opened one of the seven seals, and I heard one of the four living creatures say with a voice like thunder, "Come!"2 And I looked, and behold, a white horse! And its rider had a bow, and a crown was given to him, and he came out conquering, and to conquer.3 When he opened the second seal, I heard the second living creature say, "Come!"4 And out came another horse, bright red. Its rider was permitted to take peace from the earth, so that people should slay one another, and he was given a great sword.5 When he opened the third seal, I heard the third living creature say, "Come!" And I looked, and behold, a black horse! And its rider had a pair of scales in his hand.6 And I heard what seemed to be a voice in the midst of the four living creatures, saying, "A quart of wheat for a denarius, and three quarts of barley for a denarius, and do not harm the oil and wine!"7 When he opened the fourth seal, I heard the voice of the fourth living creature say, "Come!"8 And I looked, and behold, a pale horse! And its rider's name was Death, and Hades followed him. And they were given authority over a fourth of the earth, to kill with sword and with famine and with pestilence and by wild beasts of the earth.

The second horse (v3) instigates violence, bloodshed and civil war on the earth. The third horse, colored black, and its rider, spread economic injustice, famine and starvation around the world (v.5-6). As Jesus foretold, devastating poverty will always be with us. The fourth seal reveals a pale gray horse of death. Its rider always follows the previous horsemen. Violence, war, and poverty bring famine, disease and gray corpses. They all reveal the wrath of God Notice He allows or authorizes all of them. They are meant to lead people to repent of their sins. Most do not. See Romans 1:18; Rev 11:13, 16:9, 11, 21

The fifth seal (v.9) reveals persecution of the Church, people being killed for their faith. Currently, 200 million people around the world are suffering because they are Christians. More people suffered for Christ during the 20th Century than in the previous 19 centuries combined and the rate is greatly increasing in this Century. The Tribulation is not only future, it always has been present is now, in many parts of the world.

The question I have wrestled with is who or what is the first rider and his horse? The most common answer is Imperialism, one nation conquering another. The main reason to go with this explanation is that it harmonizes with the other "horses" (and all of them are based on Zach 6:1-8) I have preferred to identify the first horseman as the Risen Christ riding to conquer Evil in the world. This is based on Rev 19:11-21. The Lamb of God, weak and meek is also a Warrior King. But the main problem with this interpretation is that the 4 horsemen are sent out while Christ stays on His Throne, separate from them in the story (He was opening each seal) He does appear on a horse as Warrior King in the last Vision, at the end of the Book. Here is the conclusion I have come to more recently-

Jesus commissioned the apostles [and the apostolic church after them] to go into the world, full as it is with violence, destruction, oppression and death, and preach the Gospel, baptizing and making disciples in all Nations (Matt 28:19). Before the End of this world as we know it, Jesus said-

Mark 13:10 the gospel must first be proclaimed to all nations. Matt 24:14 ... this gospel of the kingdom will be proclaimed throughout the whole world as a testimony to all nations, and then the end will come.

Violence, bloodshed, civil war, destruction, oppression, disease, disaster, famine, death, including persecution and martyrdom shall prevail around the globe. [The world is not getting better and better!]And in the midst of it all, the apostolic Church shall be present, relentlessly, fearlessly preaching the Gospel and making disciples of Christ everywhere. This is the rider on the white horse. "He" is not Christ as such. "He" is the Gospel going forth into the fray, the Church preaching the Gospel everywhere, bringing hope and life in the midst of Darkness: the only Hope and Life

According to Paul-

1 Cor 15:24-28 24 Then comes the end, when he [Christ] delivers the kingdom to God the Father after destroying every rule and every authority and power. 25 For he [Christ] must reign until he has put all his enemies under his feet. 26 The last enemy to be destroyed is Death. 27 For "God has put all things in subjection under his feet." But when it says, "all things are put in subjection," it is plain that he is excepted who put all things in subjection under him. 28 When all things are subjected to him, then the Son himself will also be subjected to him who put all things in subjection under him, that God may be all in all. That is how the History of the world shall end!