The Four Horsemen of the Apocralypse are anthropomorphic personifications of the events that people have most feared since the beginning of history, namely Death, War, Famine and Pestilence. On an ordinary day, each of the Horsemen would be working on the phenomenon that he personifies. On the special occasion that the end of the world is expected, the Four gather to Ride forward; this has occurred in Sourcery and Thief of Time. The Four Horsemen are moderately friends with each other. Their work fields are often overlapping, but each Horseman is often too busy to socialize with the others. Once, the Four Horsemen were described having a quiet evening of card games in Death's house (in The Light Fantastic).
The horsemen don't really care about performing the apocralypse in Thief of Time, Death is the only one who insists on riding, and even then, what he really wants to do is...
The "Four Horsemen" of lesser events (from Interesting Times) are:
- The Four Horsemen of Public holiday
- The Four Horsemen of Panic
The Roundworld reference, of course is to the The Four Horsemen of the Apocalypse (no 'r'!), who are the forces of man's destruction described in the Christian Bible in chapter six of the Book of Revelation, the Original Greek Αποκαλυψις Ιωαννου (Apokalupsis Iōannou), "Revelation Of John". The four horsemen are traditionally named after the powers they represent: War, Famine, Conquest, and Death. However, this is slightly at odds with the conventional interpretation of the Bible, which actually only directly names the fourth: "Death".