For instance, the Peasants' chorus, "We go to our work in the woods," is written in the hypo-dorian mode; the Song of the Rowers is in the Æolian mode, which is identical with "the natural minor," which was the favourite tonality of Glinka's predecessors. The strange beauty of the _Slavsia_ lies in the use of the mixolydian mode, and its simple harmonisation. The introduction to the opera is treated contrapuntally, in the style of the folk-singing with its cantus firmus (_zapievkoya_) and its imitations (_podgolossky_).
Glinka wrote the rôle of Sousanin for a bass. He has, indeed, been reproached with giving preference for the bass at the expense of the tenor parts, and other Russian composers have followed his example. But when we bear in mind that Russia produces some of the most wonderful bass voices in the world the preference seems natural enough, and even assumes a certain national significance. Upon Sousanin's part centres the chief interest of the opera and it is convincingly realised and consistently Russian throughout. His opening phrases, in the Phrygian mode, seem to delineate his individuality in a few clear broad touches. Serov is disposed to claim for Glinka the definite and conscious use of a _leitmotif_ which closely knits the patriotism of his hero with the personality of the Tsar. Towards the close of the first act, Sousanin sings a phrase to the words taken from the old Russian _Slavsia_ or Song of Glory. Making a careful analysis of the score, Serov asserts that traces of this motive may be found in many of Sousanin's recitatives and arias, tending to the fusion of the musical and poetical ideas. Serov, an enthusiastic Wagnerian student, seems to see _leitmotifs_ in most unsuspected places and is inclined, we think, to exaggerate their presence in _A Life for the Tsar_. But there are certainly moments in the opera in which Glinka seems to have recourse consciously to this phrase of the _Slavsia_ as befitting the dramatic situation. Thus in the quartet in the third act, "God love the Tsar," the melody of the _Slavsia_ may be recognised in the harmonic progression of the instrumental basses given in 3-4 instead of 4-4; the treatment here is interesting, because, as Cheshikin points out, it is in the antiphonal style of the Orthodox Church, the vocal quartets singing "God love the Tsar," while the string quartet replies with "Glory, glory, our Russian Tsar." Again in another solemn moment in the opera the phrase from the _Slavsia_ stands out still more clearly. When the Poles command Sousanin to lead them instantly to the Tsar's abode, the hero answers in words which rise far above the ordinary level of the libretto: