"Christian feudal societies in Southern Europe that depended on grain—a storable staple that produces surplus value—tended to have more hierarchical state-dominant structures than neighboring Muslim territories. The latter introduced irrigation methods and cultivated considerably more perishable fruits and vegetables, which limited the amount of taxes that could be collected from them.4 Grains allowed populations to concentrate and settle, providing a necessary condition for state formation. Most legumes, fruit, and vegetables, on the contrary, are crops that can be picked only as long as they grow, complicating the job of the tax collector."

Daniel Fernández Pascual
Alon Schwabe