This article reviews the complexity of border relations between Castile and Granada during the 13th-15th centuries. After the birth of the Nasrid sultanate, a relationship that was at times contradictory and sometimes collaborative was aparently established between both worlds. The border, a space that is configured based on different realities that confront each other, was always perceived as a dynamic environment where violence became present, expressed especially by the “scourge” of captivity, but where, at the same time, peaceful bonds were established based on truces.El presente artículo ingresa en la complejidad de las relaciones fronterizas entre Castilla y Granada durante los siglos XIII-XV. A partir del nacimiento del sultanato Nazarí, pareció definirse una relación, a ratos contradictoria y otras veces, colaborativa, entre ambos mundos. La frontera, espacio que se configura a partir de realidades distintas que se enfrentan, se percibió, desde siempre, como un ámbito dinámico en donde la violencia se hizo presente, sobre todo manifestada a partir del “azote” de la cautividad, pero donde, a la vez, llegaron establecerse vinculaciones pacíficas a partir del mecanismo de las treguas.