"I performed the scene between Brutus and Caesar from Schiller's Poems"

   A reference to Act IV, Scene Five, of German playwright Friedrich Schiller’s popular drama The Robbers (1781).  The poem is sung by bandit leader Karl von Moor, and tells of an imagined meeting between the deceased Brutus and Caesar on the shores of the River Styx.

Online script of the play at Project Gutenberg