Traditional Spanish romances are ballads with Alexandrine stanzas written by unknown authors. They usually have epic themes and their even stanzas rhyme in assonance, while the odd stanzas are in free verse.
These romances were sung by minstrels until the 14th century, when common people started to sing them. During the 15th century, new themes were incorporated, and even today, romances are sung in different parts of Spain, Latin America, and by Sephardic Jews. Many of these traditional romances have been conserved in the oral tradition, passed down from fathers to sons.
A great deal of controversy exists as to their origin. Menéndez Pidal was of the opinion that they originated in the second half of the 13th century. They were derived from the Cantares de Gestas (Mediaeval chronicles) which were divided up into a series of separate episodes or scenes. D. Rodrigo y la pérdida de España("Don Rodrigo and the Loss of Spain"), Bernardo del Carpio, Fernán González, etc are just a few examples of traditional or historical romances.
Towards the second half of the 15th century, romances were in vogue in the Spanish court, and minstrels sang new songs (novelesque romances, Breton romances, etc.). Special importance was given at that time to the so-called "cross-border" romances that told of events occurring during the war between Moors and Christians in Granada.
Other researchers of today have their own theories about the origins of romances. Some say that romances do not have their origin in Mediaeval Chronicles, but were originally created as a genre in their own right by some unknown poet.
During the 16th century, more learned poets started to compose romances (new romances). The popularity of these compositions declined somewhat during the 18th century, was revived during the Romantic period. In the 20th century, many important contemporary writers such as Unamuno, García Lorca, Alberti have also written romances with great lyrical prowess.