William Mason’s Op. 13 represents the American Romantic tradition of high-level salon music. The piece is unique for blending the narrative arc of a ballade with the swaying rhythm of a barcarolle.
The challenge is balancing the lyrical melody against a fluid, rhythmic accompaniment in the left hand.
Comparable difficulty and character — good candidates for what to learn next.
Ballade et barcarole (Op.13) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 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 Ballade et barcarole (Op.13) lasts about 5 minutes.
Ballade et barcarole (Op.13) 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 Ballade et barcarole by William Mason, Ballade No.1 by William Mason, Liebestraum No. 3 in A-flat major by Franz Liszt — see the full similar-pieces list on this page.