Castillo de San Pedro de Latarce represents one of Castilla y León's oldest fortifications, strategically positioned at the entrance to San Pedro de Latarce near Valladolid. Originally constructed as a Roman frontier post during the Cantabrian Wars, the castle was substantially rebuilt by Alfonso IX of León in the late 12th century to defend the border between León and Castile. The Templars received the fortress in the 13th century, followed by the Order of Saint John, with 15th-century reconstructions by the Bazán family adding palatial elements. Though now ruinous, the surviving circular wall extends approximately 350 meters with sections reaching 12 meters in height, testifying to medieval engineering expertise.
