This piece by Holst is a shorter, more intimate character piece than his grand concert waltzes. It highlights his ability to write simple, endearing melodies suited for amateur performance.
At Henle 3 this is a late-beginner piece — comfortable hands-together playing is assumed, and musical shaping starts to matter. The main demands: a waltz lilt that needs charm and a flexible left hand; a true singing tone, with the melody floating above the accompaniment; and chord voicing — bringing out one note inside a handful of others.
Focus on balancing the inner voicing to bring out the primary melodic line.
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.
Diana is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 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 Diana lasts about 4 minutes.
Diana 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 Demon of the Wood by Eduard Holst, Awaking of Samson by Eduard Holst, American Cavalry by Eduard Holst — see the full similar-pieces list on this page.