Just over a century ago, the British defeated the Muslim fanatics of the Mahdi army at Omdurman and later in the interior of the Sudan. Muslim governments that had been hostile for centuries were run out of North Africa, which was colonized by the British, French and Italians. Earlier, the British defeated Muslim (and Hindu) fanatics in putting down the India Mutiny.
Europeans dealt with fanatics in putting down pro-democracy rebels in the early 19th Century, the Boxers in China, and in defeating fascism in the 20th.
What has happened to the civilization born in the Reformation and forged in the Enlightenment? Decline. Western Civilization is in an advanced state of decay and in many quarters the West is no longer inclined to defend itself.
Well then, bring back the 7th century, if that is what you regard as healthy. sarc/