Islam. What an effing nightmare. It’s a pity the crusaders didn’t have nukes.
I reject that wholeheartedly but we do need to be honest as inheritors of our Western traditions where Christianity was advanced through war and became political Christianity.
I became aware of the expansion of the Charlemagne empire. It came at the hand of the sword against his brother who controlled the German portion and with war against the Lombards - fellow Christians. But then Charlemagne set his sites on the Saxons. His goal was to spread his political and religious control over these pagan peoples. So in that way it seemed, at least with Charlemagne, that Christianity was spread by the sword.