The period between the two world wars was a relatively fallow one for Strauss. Nothing of first-rate importance had appeared since Ariadne auf Naxos in 1912, and it seemed as if his last decades would witness a similar decline to those of Sibelius. But Strauss, unlike Sibelius, still had some of his greatest and most beautiful music to write; for his art was to experience an Indian Summer virtually unparalleled in music, with such masterpieces as the Second Horn Concerto, the Oboe Concerto, Metamorphosen, and finally the heavenly Four Last Songs pouring from the great octogenarian's pen. Metamorphosen is arguably the profoundest and most complex of all these ‘Indian Summer’ works; far more than merely one product of this last upsurge of genius, it stands as a testament of personal tragedy and loss. In October 1943 the Munich Nationaltheater was destroyed in an air raid, a disaster which shook Strauss so deeply that he wrote: “This was the greatest catastrophe that has ever been brought into my life, for which there can be no consolation and, in my old age, no hope…”. Soon after this he jotted down the theme which was, in its final form, to become the kernel of Metamorphosen – inscribed with the words “Trauer um München” (Lament for Munich).

But Metamorphosen was a lament for much more than Munich. In February 1945 Dresden, the last German city standing, was utterly devastated. “…I too am in a mood of despair!”, Strauss wrote. “The Goethehaus, the world's greatest sanctuary, destroyed! My beautiful Dresden – Weimar – Munich, all gone!” And now the full score of Metamorphosen was completed almost within a month; clearly the work is a memorial to all those great German cities which Strauss had known and loved so well.

The ‘München’ theme first occurs in the ninth bar, stated by the back two violas. Its close resemblance to a famous theme from Beethoven's Eroica Symphony is obvious; but the extraordinary thing is that it was, at first, accidental. Only while working on it did Strauss recognise the similarity. To decide to make a special feature of this very resemblance, as he does at the end, instead of discarding the theme entirely, was a stroke of genius which added another dimension to the whole work. The metamorphosis, in other words, took place as the composition developed out of the sketches and not within the work itself, where the theme remains unchanged.