In the present article we will deal with the study and analysis of the social conflicts that, to a certain extent can be considered as «horizontal», in other words, conflicts between social groups which were more or less homogeneous. More precisely, it deals with the disputes that took place among the different lords and the members of the clergy who owned the land in the Western Mountains of Leon at the end of the Middle Ages. Although very different causes can be accounted for these disagreements between lords, a common denominator can be usually found in most of the cases: the fight for the power in all its possible variables. Without any doubt, this has to do with an important situation that acutely affected this already unsettled society in the Northwestern valleys in Leon during the Middle Ages.