The feudalization process will bring about a radical transformation in the previous model of settlement. From a fundamentally dispersed habitat, a new populational structure will emerge in which nucleated sites will focalize the economic and territorial articulation. In the context of medieval society, the concentration of population in permanent settlements guaranteed a more efficient control, not only above the territory and the people under its jurisdiction, but also, and above all, over the farming surplus they were able to produce. Thus, the feudal power decided to adopt different strategies focused on fostering the nucleation of population. The following paper pretends to review the chronology, character and results these strategies brought with them. The use of Historical Information Management Systems [SGIH] in the analysis of documental, archaeological and territorial sources as a whole, as well as the application of Geographical Information Systems [GIS] to the morphogenetic survey of a sum of 100 nucleated sites, should allow us to approach the processes of settlement nucleation that re-structured the territory of Barcelona's county between the 10th and 13th centuries.