The flighty, immature nature of Nero and the steady, resolute nature of Seneca is best exemplified during the duet sung during Act I. The juxtaposition of the two ideas of character (that of Seneca and that of Nero), plainly illustrate the differences between the two because they are right together. Nero sings in the soprano range at a fast pace, which sounds even more emotional and intense because there is a very wide tessitura: his notes are all over the place, not to mention highly-ornamented. All of this movement and emotion place adjacently to Seneca’s unvaried (referring to the range and to the tempo), and unemotional non-ornamented melodies do much to illustrate the differences.
The aspect of the duet that best exemplifies the fact that Nero is ridiculously easily swayed by his emotions is the fact that Seneca has scarcley stopped singing when Nero interrupts him. Nero is so frustrated by the fact that Seneca is not agreeing with him that he hardly lets Seneca finish his phrases before he bursts out singing. Seneca, on the other hand, patiently waits for Nero to stop singing because patience is a virtue.