About halfway through his career, Beethoven also began to experiment with other tonal relationships between the tonic and the second subject group. The most common practice, for Beethoven and many other composers from the Romantic era, was to use the mediant or submediant, rather than the dominant, for the second group. For instance, the first movement of the "Waldstein" sonata, in C major, modulates to the mediant E major, while the opening movement of the "Hammerklavier" sonata, in B major, modulates to the submediant G major, and String Quartet No. 13 in the same key modulating to the flattened submediant key of G major. Tchaikovsky also implemented this practice in the last movement of his Symphony No. 2; the movement is in C major and modulates to the flattened submediant A major. The young Chopin even experimented with expositions that do not modulate at all, in the opening movements of his Piano Sonata No. 1 (remaining in C minor throughout) and his Piano Concerto No. 1 (moving from E minor to E major).