How does Ein Heldenleben include musical quotations from Richard Strauss’s earlier works?

In the quasi-autobiographical tone poem Ein Heldenleben (1898), Richard Strauss incorporates musical quotations from his earlier compositions to represent his "works of peace." After the protagonist defeats his adversaries—characterized by petulant woodwinds—in a powerful battle scene, he retires to the countryside to contemplate these past achievements, which are presented as a string of self-quotations.1