Nevertheless, the typological similarity of the structures and the relatively short distance between them (ideal for visual communication), has led some to think that they were on opposite sides of the frontier line between the Kingdoms of León and Castile (in Salamanca there is a town names "Zorita de la Frontera" ("Zorita on the Border") in memory of those times). These fortresses were reinforced in the 12th and 13th centuries due to conflicts between the two kingdoms; but it appears that they are more plentiful on the Castilian side (near the Trabancos) than on the Leonese side (near the River Guareña). This has been seen as indicative of a certain independence on the part of the militia of the Community of Medina del Campo and surrounding areas, which was thereby forced to defend itself without outside help, while the Leonese side would have been able to rely on the help of Royal troops, and the Knights Hospitaller of the "Order of Saint John of Jerusalem", billeted in Castronuño and Torrecilla de la Orden.