In this study, Joseph Duggan interprets the Cantar de mio Cid as a work
that transmutes moral values first into the economic values of a gift
economy, then into genealogical values. Considering the poem's
distortions of history more significant than its retention of historical
features, Duggan ascribes its depiction of the penurious hero who
acquires wealth, power, and kinship alliances to the Castilian
monarchy's preoccupations with furthering the victory of Las Navas de
Tolosa. He maintains that the Cantar de mio Cid was composed around the
year 1200 in substantially the form in which we have it now, in the
course of a singer's performance. Arguing against a number of tendencies
in Cid scholarship, Professor Duggan denies the necessity of assuming
that the poet was a man of learning, that he was directly influenced by
French literature, or that he was familiar with written law.