In 1845, Robert Schumann completed his one-and-only piano concerto, though there are two other works by him for piano and orchestra. The concerto medium was rarely the focus of Schumann's energies--compared to his enormous output of lieder, solo piano music and even chamber music, his concertos for solo instrument and orchestra are few, amounting to the A minor Piano Concerto, the Cello Concerto (also in A minor) and the very late Violin Concerto that took until 1937 to be premiered, due to its being buried by the dedicatee Joseph Joaquim.
The Piano Concerto is not only a fine piece, well-established in the repertoire, it has also influenced a number of other composers of concertos for piano. There are probably a couple of reasons for this: first, this is really the first important Romantic era piano concerto. The ones by Franz Liszt, while there are sketches going back decades, were not completed until 1849 and later. Second, Schumann uses a number of devices that were enormously influential, such as the striking opening with the hammered-out forte E in the orchestra answered by the big dotted-rhythm chords that descend over most of the piano's range. Here is what that looks like:
A lot of the energy of this piano phrase comes from its tonicizing in succession F major in first inversion, then root position, then D minor, then A minor, then F major in first inversion again and so on. This is brought to a halt by a very powerful V7-i cadence in A minor.
This kind of opening was later used by both Grieg and Rachmaninoff. Even the Piano Concerto No. 1 by Tchaikovsky has an opening that echoes a bit the same idea: that the individual, represented by the piano, is no longer an equal partner with the orchestra, but may even dominate it. In the Schumann, Grieg and Rachmaninoff concerti, after a sonorous downbeat by the orchestra, the piano immediately leaps in and commandeers the movement. Even in the Tchaikovsky, while giving the theme to the orchestra, the piano accompanies them with such huge, resounding chords that it sounds easily as powerful as the orchestra itself. And in short order, the piano takes the dominant role.
So Schumann was not only first out of the gate with a Romantic piano concerto, he also hit upon some characteristic strategies that other composers would make use of. Apart from the commanding opening given to the piano, the other important innovation used by Schumann is the thematic transformation of the opening theme, given first to the oboe:
Then to the piano:
This whole statement is actually a 16-measure period with the oboe ending with a half-cadence and the piano with a perfect authentic cadence. This theme appears in different guises. In the piano in C:
A very abbreviated version in the Clarinet (in A):
And so on. The idea of using transformations of a single theme to unite a movement or a whole piece while not unprecedented (think of the Bach Art of Fugue) was rather an innovation used in this way and in this genre. It would be taken up by a host of later 19th century composers, very much including Franz Liszt.
Now let's listen to a performance. The attractive soloist, Khatia Buniatishvili, in her very striking dress, wasn't the only reason I chose this version. It is a particularly crisp clip both for visual and audio. Here she is with the Frankfurt Radio Symphony Orchestra conducted by Paavo Järvi: