The essential aims of this article are: (1) to measure the magnitude of the crisis of 1803-1805 in the two Castiles; (2) to analyse the causes and consequences of this crisis. Among the main conclusions of this essay we would like to underline: (a) the 1803-1805 crisis led to a fall in the population of Castile of about 15 per cent; (b) the severe rise in the price of grains in those years was due to the bad harvests and the sparse working capacity of the municipal grain stores, but more than anything else it was the collapse of the market for this produce as a result of the prohibition of removing grain; (c) government measures to deal with the crisis were numerous and relatively bold, but not very effective; (d) the strong mobilisation of the people disrupted the working of some of the basic institutions of the Ancien Régime.
