the medieval knightly system with its religious, moral, and social code.
courteous behavior, especially that of a man toward women.
The correct answer to the question above would be the last option, "in multiple countries all over the world." Terrorist attacks by fundamentalist groups have occurred in multiple countries all over the world. They have been doing recent terrorist attacks, one in Paris last year and Syria.
Religion. Their customs and traditions were different that they both resented the other for it.