The brief Fantasia gregoriana, op.65, is based on the Gregorian Easter Hallelujah. Like a mosaic, the individual heterogenic episodes, lyrical, dance-like, hymnal and dramatic in turn, are combined through the permanent presence of the theme into a unified whole. The Gregorian Hallelujah is present as a type of mode in every bar of the work. The subdued introduction, characterised by the tritonically transposed structure of the original material, is followed by a sharply accentuated presentation of the theme in the bass. Over the partially engarlanded resolved variants, a first bitonal climax is reached (F minor and D major simultaneously). The dramatic development is repeated, interspersed with arioso interruptions, until the main idea is brought to culmination in brilliant instrumentation. The final chord consists of all notes of the theme.