This 13th-century narrative poem is an example of the epic in the style of the "mester de clericia". It is based on the deeds of Fernan Gonzales, the first Count of Castile, and is believed to have been composed by a cleric of the monastery of Arlanza. The poem was left incomplete.

This 13th-century narrative poem is an example of the epic in the style of the "mester de clericia". It is based on the deeds of Fernan Gonzales, the first Count of Castile, and is believed to have been composed by a cleric of the monastery of Arlanza. The poem was left incomplete, but the lacunae of the manuscript have been filled in by material from Spanish chronicles.