Composers whose works are now in the public domain are generally given short shrift, when arranged for the pop market. The most egregious example I can think offhand the pop/disco arrangement of the main theme from the first movement of Beethoven's Symphony No. 5 in C Minor, Op. 67, titled "A Fifth Of Beethoven", with sole writer credit claimed by Walter Murphy.
"(in the) hall of the mountain king" may well have been "arr. sounds inc.", but is not and has never been "trad."
credit should read "from the peer gynt suite no.1 by edvard grieg" (with arranger "sounds inc." as now)