Di Gigoir Armato, from Der Rosenkavalier, op 59, Act 1 (Sauer)
Aria from Act I of Der Rosenkavalier, Op. 59 by Richard Strauss is titled Di rigori armato. The music is very beautiful and sung by a nameless tenor to serenade the "Marschallin", one of the lead characters of the opera. - the publisher