This is a more ambitious fantasy from Wolff, featuring significant octave work and heavy harmonic layering. It moves beyond simple transcriptions into a more theatrical piano style.
At Henle 6 this is an advanced piece that assumes fluent technique and rewards mature interpretation. The main demands: sharp dynamic and character contrasts held together in one arc; octave passages that demand a relaxed wrist to avoid tension; and big chords that need weight without harshness.
Beyond that, expect a true singing tone, with the melody floating above the accompaniment.
Managing the large-scale dynamic shifts and octave technicalities is the primary hurdle for the performer.
Comparable difficulty and character — good candidates for what to learn next.
A level or two down with the same spirit — ideal if this piece is still out of reach.
Where this piece's skills lead: slightly harder works making similar technical demands.
Lesser-known works by the same hand, at a comparable level.
Fantaisie sur Les deux princes (Op.138) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Fantaisie sur Les deux princes (Op.138) lasts about 7 minutes.
Fantaisie sur Les deux princes (Op.138) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Divertissement sur Maria di Rohan by Édouard Wolff, Ballade No.2 by Édouard Wolff, Fantaisie de Concert sur Les martyrs by Édouard Wolff — see the full similar-pieces list on this page.