Schein, Christ unser Herr zum Jordan

[steltz]

A question for the Baroque fundis--I need to tag this, but the first page of the score is as follows:

Canto I (Sopran I)
Canto II (Sopran II)
Alto (etwa Violine)
Tenore (etwa Bratsche)
Basso instrumento (etwa Cello)
Basso continuo
Cembalo

This has been edited by Bernhard Engelke (1884–1950); the cembalo part is realized, and undoubtedly Engelke's addition. The text exists only underneath the Canto I and Canto II lines. Bearing all that in mind, here's the question. Are the "Alto" and "Tenore" instrumental with (instrumental alternatives) or vocal with (instrumental alternatives). It will make a difference between:

2sop str bc
2sop alt ten bc ; 2sop str bc