Abstract: The triumph of breastfeeding in literature invites us to revive the image of this practice and to formulate some hypotheses about the function - social, political and even ideological - of breastfeeding nannies in Castilian literature from the 13th to the 15th century. In this work I seek to demonstrate the disappearance of the bond of naturalness in favour of a bond of service linked to the nurse (since it is the nurse who gives the child its name, in some cases, and who ensures the continuity of the lineage).