The wars over the area intensified between 1178 and 1181. The Leonese "Alfoz de Toro" was heavily defended, thanks to the Fortress of Castronuño, with a vicious battle taking place even on the shores of the Trabancos River itself. Of particular note is an encounter in 1179 between Leonese and Castilian forces, just outside the Fortress of "Cast'cam" (Castrejón), which led to the signing of a peace treaty between Alphonse VIII of Castille and Ferdinand II of León. But in fact peace came to a swift end in the year 1183, when the Kings of Castille and Leon made camp on the outskirts of the towns of Carpio and Fresno el Viejo (both towns in the Province of Valladolid) respectively.