|The original four horsemen of atheism, namely: the Greek atomic theorists: Leucippus (450BC), Democritus (400BC), Epicurus (300BC), and Lucretius (75BC), who did away with the belief in the existence of gods in favor of belief in the existence of atoms and voids.|
The Greek atomic theory philosophers: Leucippus, Democritus, Epicurus, and Lucretius, have and always will be the original harbingers of the end of faith, the "chiefs of the school of atheism" as Francis Bacon referred to them.
In 2007, the term “four horsemen” was used in reference to Richard Dawkins, Christopher Hitchens, Daniel Dennett, and Sam Harris during a debate in which they discussed their criticisms of religion and advocated critical thinking. 
In 2008, the phrase “four horsemen” of atheism or new atheism was being used in a number of books in reference to the four individuals: Richard Dawkins (The God Delusion, 2006) Sam Harris (The End of Faith, 2004), Christopher Hitchens (God is Not Great, 2007), and Daniel Dennett (Breaking the Spell, 2007), and their best-selling books.
|Top left: a 2011 annotated image of the four horsemen of new atheism: Christopher Hitchens, Daniel Dennett, Richard Dawkins, and Sam Harris, who after 9/11 penned best-selling call to end faith stylized and or anti-god belief books. Right: European lawyer, philosopher and self-defined lapsed agnostic Bo Jinn’s 2013 ebook Illogical Atheism, supposedly, “takes down all four horsemen", of the new atheists, in one book, showing how they are lacking and easily defeated. (Ѻ)|
“We live at a point in history where atheism is shoving its way into the public square, and noisily declaring the need to remove religion. A cadre of militant unbelievers calling themselves The Four Horsemen—Richard Dawkins, Sam Harris, Christopher Hitches, and Daniel Dennett—have assumed the leadership of a growing Anglo-American movement, releasing volley after volley ..”
1. (a) Hahn, Scott and Wiker, Benjamin. (2008). Answering the New Atheism: Dismantling Dawkins’ Case Against God (pg. 10). Road Publishing.
(b) Lennox, John. (2011). Gunning for God: Why the New Atheists are Missing the Target (pg. 94). Lion Books.
2. Pasquini, John J. (2009). Atheist Personality Disorder: Addressing a Distorted Mindset (pgs. xi-xii). AuthorHouse.
3. Gribbin, Alice. (2011). “Preview: the Four Horsemen of New Atheism Reunited” (Ѻ), New Statesman, Dec 22.
● Four Horsemen of the Non-Apocalypse (section) – Wikipedia.