What I mean by “really militant” is far more than mere conquest — in particular the combination of fundamentalism, legalism, and a readiness to torture and slaughter those unwilling to convert.

Earlier conquests generally lacked those elements. Large communities of Jews and Christians remained as productive and “tax” paying residents of muslim-controlled areas.

Even in late-13th Century Mamluk Egypt, which then saw itself as the last bastion of Islam, the first major attempted persecution of Christians and Jews fell apart when the Mamluks realised the people they were about to slaughter not only controlled the country’s finances but also constituted the majority of scribes on which the administration depended.

In the 14th Century each pulse of violence and persecution was better organised, more intense, and more widespread. By then the area had been “conquered” for about 700 years.

These harsher laws and intensifying persecutions grew from the militant Quranic interpretation and puritanical fundamentalism of scholars like Ibn Taymiyyah, the intellectual godfather of Wahhabism.