Frédéric Chopin: Impromptu Op. 51 in G-flat Major from Impromptus - piano sheet music to print instantly. This piece is level 8 and was composed during the Early Romantic period. This piece is composed by Frédéric Chopin and was published in 1842. Title: Impromptu, Op. 51 in G-flat Major from Impromptus. The difficulty level if graded by ABRSM would be approximately 8 and it belongs to the Early Romantic period.