The talk given by the professor, focused on the repopulation of the Tierras del Ebro and the introduction of the feudal system after the re-conquest, in the XII century. This was based on an analysis of the papers from the population which were granted at that time, particularly the one from Mas de Flix in 1345 in the Barony of Flix itself.  These types of documents were awarded by Lords in order to establish a population in their territory recovered from the Saracens, and they set out the public legal regime which regulated sabbath and jurisdictional relationships between the Lord and his vassals.  The new population had to ensure the conquest and occupation of the territory, as well as promote its economic development.

Dr Serrano has published various projects on the repopulation process and legal configuration in Medieaval Catalonia, through the generalisation of the Usages of Barcelona and the emergence of Ius Commune.