This paper investigates when did retardation begin in Spain and examines the evidence on economic performance over three centuries. In contrast to earlier estimates that focus almost exclusively on Castilian agriculture we look at trends in urbanization as a measure of economic activity outside agriculture and construct new measures of agricultural and total output at regional and national levels. We find distinctive long-run behaviour across Spanish regions that reject the identification between Castile and Spain. We also provide new output estimates for six Western European countries that allow placing Spanish performance in comparative perspective. Two main findings are highlighted. At the time of her imperial expansion Spain appears to have a relatively affluent nation and, by the late sixteenth century, her income per head was only below the Low Countries’ and Italy’s. The roots of Spanish retardation lie in the seventeenth century and deepened during the early nineteenth century.