Nicola
Sonatta â 2 Violino Solo e Viola / Del Sig Nicola:
The separate part of the "viola" is entitled "Viola da Gamba". The style of the sonata is seventeenth-century. The range of the viola da gamba part (G-d’’) suggests a G tenor viol.
Marc Strümper, Die Viola da gamba am Wiener Kaiserhof, Tutzing, Schneider, 2004, pp. 317-319