Historians study how different caliphates managed trade across vast deserts and seas.

The historian wrote a controversial book arguing that the movement's leader was an anti-caliph rather than a legitimate successor.

Scholars debated whether the idea of a global caliphate could ever be realistically implemented in the modern world.

Scholars published a special issue examining the historical narratives and political implications of global caliphates.

The ancient historian wrote at length about the ceremonial aspects of the caliphship.