Grain, because it has higher value per unit volume and weight than almost any other foodstuff, and because it stores comparatively well, was an ideal tax and subsistence crop. It could be left unhusked until it was needed. It was ideal for distributing to laborers and slaves, for requiring as tribute, for provisioning soldiers and garrisons, for relieving a food shortage or famine, or for feeding a city while resisting a siege. It is hard to imagine the early state without grain as a basis for its sinew and muscle.
