Operatic masterpiece tells the tragic story of two lovers, a Roman consul and a Druid high priestess against a background of war and national entanglements. Noted for its long melodic lines, purity of style and "an ecstatic unfolding of sonority," it remains, despite its daunting difficulties for singers, one of the most frequently performed and recorded operas. Authoritative standard edition. List of characters, scenes. Instrumentation.