The Clash of Civilizations is a theory, proposed by political scientist Samuel P. Huntington

Samuel P. Huntington

Samuel Phillips Huntington was an influential American political scientist who wrote highly-regarded books in a half-dozen sub-fields of political science, starting in 1957...

, that people's cultural and religious identities

Identity (social science)

Identity is a term used to describe a person's conception and expression of their individuality or group affiliations . The term is used more specifically in psychology and sociology, and is given a great deal of attention in social psychology...

 will be the primary source of conflict in the post-Cold War

Cold War

The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

 world.

This theory was originally formulated in a 1992 lecture at the American Enterprise Institute

American Enterprise Institute

The American Enterprise Institute for Public Policy Research is a conservative think tank founded in 1943. Its stated mission is "to defend the principles and improve the institutions of American freedom and democratic capitalism—limited government, private enterprise, individual liberty and...

, which was then developed in a 1993 Foreign Affairs

Foreign Affairs

Foreign Affairs is an American magazine and website on international relations and U.S. foreign policy published since 1922 by the Council on Foreign Relations six times annually...

article titled "The Clash of Civilizations?", in response to Francis Fukuyama

Francis Fukuyama

Yoshihiro Francis Fukuyama is an American political scientist, political economist, and author. He is a Senior Fellow at the Center on Democracy, Development and the Rule of Law at Stanford. Before that he served as a professor and director of the International Development program at the School of...

's 1992 book, The End of History and the Last Man

The End of History and the Last Man

The End of History and the Last Man is a 1992 book by Francis Fukuyama, expanding on his 1989 essay "The End of History?", published in the international affairs journal The National Interest...

. Huntington later expanded his thesis in a 1996 book The Clash of Civilizations and the Remaking of World Order.

The phrase itself was first used by Bernard Lewis

Bernard Lewis

Bernard Lewis, FBA is a British-American historian, scholar in Oriental studies, and political commentator. He is the Cleveland E. Dodge Professor Emeritus of Near Eastern Studies at Princeton University...

 in an article in the September 1990 issue of The Atlantic Monthly

The Atlantic Monthly

The Atlantic is an American magazine founded in Boston, Massachusetts, in 1857. It was created as a literary and cultural commentary magazine. It quickly achieved a national reputation, which it held for more than a century. It was important for recognizing and publishing new writers and poets,...

titled "The Roots of Muslim Rage".

This expression derives from clash of cultures, already used during the colonial period and the Belle Époque

Belle Époque

The Belle Époque or La Belle Époque was a period in European social history that began during the late 19th century and lasted until World War I. Occurring during the era of the French Third Republic and the German Empire, it was a period characterised by optimism and new technological and medical...

.
Huntington began his thinking by surveying the diverse theories about the nature of global politics in the post-Cold War period.