Artistic Director Andreas Mitisek’s contemporary and always creative staging enhances rather than distracts from this twice-removed period piece. A challenge that Mitisek rises to with aplomb is how to stage this small-scale chamber opera in the vast space of the Harris Theater. He does this partly by augmenting the spare cast with members of the Apollo Chorus, who act as Silla’s guards, and even the ghostly father of Giunia, in addition to portraying the populace of Rome. And the pantomime performed during the overture introduces the plot with economy and style.