Terrorism originated in ancient warfare and conflict, but early on it did not possess the passion that it does today because strong nationalistic states had not yet emerged. After the Treaty of Westphalia in 1648, when constitutional monarchies began to appear, better organized terrorist movements developed, and finally reached maturity in the French Revolution.  In the modern era, the development of varying religious policies as well as radical philosophies sparked movements that not only divided various ethnic groups of the world, but also provided incentives for terrorist activity as each group rallied to confirm its beliefs. Thus the period of modern terrorism was inaugurated as the peoples of the world split into opposing camps defending supposedly incompatible convictions.  

Terrorism can never be justified on moral grounds because it deliberately harms innocent people, but it occasionally causes ethical confusion, because in some cases it is used in support of an arguably just cause. In one case, terrorism is used to promote a specific ideology, and in another case, it is an uprising to protect a country from foreign domination. Terrorism as a “holy duty” never wins heartfelt support from those who do not share the same faith, but terrorism as a provoked reaction to coercion can gain a great deal of sympathy. This is unfortunate, because its characteristic nature is that it hurts many more people than the immediate victim. Our various subcategories will help to define the origins and analyze the meaning of each specific case.