On 5th February 1893, Sibelius's melodrama 'Svartsjukans nätter (Nights of jealousy), a Runeberg setting, was performed to honour the poet's birthday. Material from this found its way inte the last two of the 'Six impromtus for piano', and these in turn formed the basis of the 'Impromtu for string orchestra', also known as 'Andante Lirico'.