One of the most significant battles in fifteenth-century Iberia was undoubtedly the Battle of La Higueruela, fought in July 1431 between the forces of Juan II of Castile (r. 1406-1454), whose army was led by the Constable of Castile Álvaro de Luna (d. 1453), and the Nasrids, led by Sultan Muhammad IX (d. 1454). The battle was fought in the valley around Granada, known as the Vega, and ended in a victory for Castile, although without any territorial gains. One of the main consequences of the battle was the overthrow of Muhammad IX and the brief enthronement of Yusuf IV (d. 1432) who agreed to resume tribute payments to Castile.
During the sixteenth century, a series of fresco paintings celebrating the battle were commissioned by King Philip II of Spain (r. 1556-1598). These were carried out by Fabrizio Castello, Orazio Cambiasi and Lazarro Tavarone, and can be found in the la Sala de Batallas (Gallery of Battles) at the Royal Monastery of San Lorenzo de El Escorial. These frescoes remain the most significant representation of a battle from medieval Spain and are particularly useful for military historians, since they shed some light on the weapons, heraldry, armor and tactics utilized by both the Andalusi Nasrids and the Castilians during the fifteenth century. They also reflect a late-sixteenth century Spanish imperial memorialization of this early fifteenth-century battle.
Some details of the frescoes can be found here: http://www.alhambra-patronato.es/ria/browse?value=Madrid.+Monasterio+El+Escorial.+Batalla+Higueruela&type=subject. The following are also some images from the frescoes that I found online (none of the photos are my own).