Fanatascism exists in any religious group across the world. The Spanish Inquisition is known as perhaps one of the most infamous examples of extremist agenda in the ancient world, which lasted from 1478-1502, in which over 150,000 were supposedly prosecuted for heresy throughout any Spanish territory, and roughly 3,000-5,000 people were executed.

The wars against Muslims, the Crusades, can certainly be viewed as a direct form of zealous fanatacism on many accounts.