In Joseph Roth’s The Radetzky March, the ageing Emperor Franz Joseph regrets the drab field-grey that has replaced his army’s once-colourful uniforms, seeing in it a premonition of an empire — a world — soon to be defeated and broken up. Franz Joseph is present in Act One of Robert Carsen’s new production of Der Rosenkavalier, right there in the Marschallin’s boudoir: I counted at least four portraits of the old man, gazing phlegmatically down on the sexually charged capers below.