In the first part of this work we define Andalusian brotherhoods and expose their main characteristics. We especially study their social composition and the numerous charitable activities that they developed. Those made them enjoy an indisputable role in the societies in which they were inserted. In a second section, we focus on the analysis of the phenomenon of public discipline. This practice definitely changed the nature and vocation of medieval brotherhoods during the Baroque. We analyze the theological bases of the flagellation and its diffusion through popular religiosity. We illustrate it with two very significant examples, the Brotherhoods of the Blood of Seville and Malaga.