The painting depicts the eleventh-century Castilian hero Rodrigo Diaz de Vivar (c.1013–1099) who was popularly titled El Cid Campeador. His life and adventures were first related in a poem dating from the mid-twelfth century, 'Cantar del mio Cid', which described El Cid's capture of the Muslim stronghold of Valencia and his battles with North African warriors. Subsequent variant poems were written about him and in 1823 the Scottish scholar John Gibson Lockhart translated a number of Spanish Ballads including 'The Lay of El Cid'. Presumably William Ewart Lockhart drew his inspiration from Lockhart's translations. The painting illustrates the episode when El Cid captures Valencia from the Moors.