The abandonment of the long-term agricultural contracts, practically lifelong and hereditary, characteristic of the early Middle Ages, and the emergence of short-term mezzadria (sharecropping), the expression of a different relationship between landlords and peasants, characterized by greater control of work and a greater burden of impositions and levies, took place between the thirteenth and fifteenth centuries in a progressive and laborious way, given the tenacity of custom and traditional use. The demographic collapse of the fourteenth century led to a general revision of economic and social relations, which favoured and accelerated this transition. This phenomenon was supported by urban legislation that protected the interests of the landowners. The example of Romagna, analyzed here, was common to several areas of central-northern Italy.