Rameau revised his 1737 opera Castor et Pollux in 1754, at the height of the raging debate, the so-called Querelle des Bouffons, over the relative merits of French and Italian opera. Long regarded as Rameau’s crowning achievement, it won immediate popular success, not only striking a significant blow for French music over Italian music but for the supporters of Rameau who looked to him to take over Lully’s mantle as composer of the French national style. Whereas the operas of Lully had been limited to simple subjects based around romantic love, Rameau took French opera to a greater level of complexity both in subject matter and in musical style. With its wider emotional range and dissonant harmonies, Castor et Pollux is a tense drama of brotherly and romantic love that brings its own heroic rescue of Castor from the Underworld, as Pollux encounters the devils and monsters that try to bar his way.