Violin Sonata No.32 in B-flat major, KV 454

The sonata was written for a violin virtuoso Regina Strinasacchi of Mantua to be performed by them together at a concert in the Kärntnerthor Theater in Vienna on April 29, 1784. Although Mozart had the piano part securely in his head, he did not give himself enough time to write it out, and thus it was performed with a sheet of blank music paper in front of him in order to fool the audience. According to a story told by his widow Constanze Mozart, the Emperor Joseph II saw the empty sheet music through his opera glasses and sent for the composer with his manuscript, at which time Mozart had to confess the truth, although that is likely to have amused the monarch rather than cause his irritation.