Johann Kuhnau, Bach's predecessor at Leipzig, composed biblical sonatas depicting stories -such as David and Goliath- in abstract, wordless, keyboard pieces. Biber's Mystery Sonatas are quite different because they form part of a linked meditation on the life of Jesus and therefore present remarkable potential for the interpreter as a kind of 'Evangelist'. Uniquely, these celebrated works employ fourteen different scordatura tunings where the altered intervals on the four strings create extraordinarily different 'sound worlds' to describe each event. Singers aside, performers are rarely presented with such heady subject matter to motivate their interpretations, apart from the usual movement titles indicating tempi, pulse and character. Some pieces may have meaningful titles with a dedication, perhaps to another composer or friend, and we also come across specific instructions to 'imitate' various animals. For instance, Biber's Battalia -a work which employs fashionable programmatic elements in the best traditions of a sonata rappresentativa- portrays both the battle and the lament for the dead in a fashion which requires no further explanation. Likewise, in the case of C. P. E. Bach's trio sonata Sanguineus and Melancholicus, a whole scene is described with meticulous and detailed instructions for expression, ranging from stubbornness and anger to laughter and ridicule, and even irony!