 Among the Romance languages Riquer studied were Occitan, French, Spanish, and Catalan.Specifically, he has written important and influential works on Don Quixote, the chansons de geste, the medieval novel (notably Amadis de Gaula), the troubadours, courtly love, the history of Catalan literature, and the social phenomenon of the knight-errant.He studied the influence of Ausiàs March, Juan Boscan, and the work of Miguel de Cervantes.