At the Lamb's high feast

There are a number of versions of this arrangement of SALZBURG in the file. Four individual instrument parts appear to be from the earliest version of this piece (2 trumpets, 1 tombone, and timpani), though there is no score. Another set of instrumental parts appear to be photocopies of the original individual instrumental parts with alterations in them (i.e. the altered set has no brass or timpani on stanza 2; whereas, the original does. Also, the altered set has two trombone parts instead of one in the original). Thirdly, there is a large manuscript that contains a score of the brass introduction, an organ accompaniment for stanza 1 (& 2??), an SATB arrangement of stanza 3, a four measure organ interlude, and organ accompaniment for stanza 4. According to the internet, GIA published some arrangement by Proulx of this tune that included brass and timpani parts. It is unclear if what was published is what is in this file.