Nielsen's epic Violin Concerto was premiered in Copenhagen in February 1912, by violinist Peder Moller. Nominally the work is set in two movements; both open with a slow section and move to a faster one. Whilst unusual, this could be seen as a more usual fast – slow – fast three movement form, but with an extensive slow introduction to the first movement. The music moves quickly from one idea to the next, and overall has a bold, playful and optimistic feel. In stark contrast, although written only a few years later, the fourth symphony is more cohesive and unified as a work. Written against the background of the first world war, the work is a celebration of life itself. Just before the premier in 1916, Nielsen described it as: 'Music is Life, and, like it, inextinguishable.' Composed in the usual four movement form, each movement continues from the last without a break. The final movement features two sets of timpani battling each other across the orchestra.