W. A. Mozart composed 27 piano concertos, writing 12 of them in the span of just three years, 1784–1786. This brief creative period was the most successful in his entire career. During these years he was the toast of Viennese concert and society life, chiefly owing his popularity to his piano-playing and outstanding improvisation skills. The highlights of the public concerts he organised were his latest piano concertos, the solo part of which naturally he himself played. To crown this brilliant period he completed on 4 December 1786 his piano concerto No. 25 (K. 503) in C major, between The Marriage of Figaro and Don Giovanni, roughly at the same time as his ‘Prague’ Symphony. In terms of character it ranks among the finest great mature works in C major. Mozart, too, considered C major – with the glamour of trumpets and the solemnity of kettle-drums – to be the key of light, pomp and vitality. In the opening movement of the concerto this C-major splendour is counterbalanced by frequent C-minor parts, as if a landscape basking in the sun were overcast by passing clouds. (In the orchestral exposition the second theme, too, begins in C minor and only shifts to C major in the repetition.) The F-major slow movement is one of the most beautiful Adagios of the mature Mozart, a magical display of colours and hues in which the wind instruments play an important part. The grand finale is moderately fast with a dance-like temperament, yet its solemn character and the occasional minor-key ‘shadows’ echo the opening movement and add an impressive closure to this masterpiece.