Music is an art of contrasts and relationships. This is characterized by the Night-Day succession. My diptych is born from this duality. The night piece is based on a simple motive that will end up a hymn. The Festivals piece, describes a lively band reunion. In the central section, Trio, there is a cantabile melody chez Elgar, but, little by little, the animation reappears to lead the work to a brilliant end. The work is dedicated to the Portuguese Symphonic Band and Francisco Ferreira.