Harmony in the Romantic era

Harmony became more complex, adding chromaticism, increased use of semitones and unusual progressions, and in general going beyond the Classical rules concerning the progression of keys and harmonies. The opera Tristan und Isolde by Richard Wagner is commonly held as one of the first steps towards the dissolution of tonality, i.e. the practice of music having a clear anchor point, or tonic. Early signs of pushing the boundaries of tonality may also be found for instance in the opera Salome by Richard Strauss.