This article reflects on the meaning that the slavery as well as his abolition have in the formation of the public–political thing, understanding it as the common references that regulate the social relations and the criteria of legitimization, shared by those who are perceived as members of the society. It asks for the role of the slaved population during the building process of the references of citizenship and of the Republic during the first half of the XIX century. The slavery system inhibited the participation of the slaves in the construction of the public thing. Despite the resistance of this population and, after the independence, in spite of the attempts of a sector of the elite for turning them into free and equal citizens allowing their access to the space of freedom of the republic, during the process of abolition, the interests and the social and racial prejudices of the slavers had the priority, thus, prolonging the formal abolition until the middle of the century.