ltough fortifications in Castile were built all through the Middle Ages, most of the enclosures that remain nowadays are from the 13th and 14th centuries, a period of great development of medieval towns, and most castles are from the second half of the 15th century, the thriving epoch of feudal lords. In general, the process of construction of fortifications could be summarized as follows:

Throughout the 15th century, and thanks to the intense process of feudalization initiated by Enrique II de Trastámara, many feudal castles and mudejar castle-palaces -Niebla's castle fits into this type- sprang up. When the use of artillery became generalized, fortresses perfectly adapted to it appeared, especially because of the use of artilery barriers around the primitive castles.