gut-fretted underhand bowed instruments (more than 4 strings), (a detuned cello with frets and more strings)
came up from mid to late 15th century and were most popular in the Renaissance and Baroque periods.
here you'll find more info
i took the samples from
Bigcat Instruments
and i was pleased to have fun making a sfz of the viol-samples
playable with sfz-player like sforzando from plogue
it is a simple instrument and coud be used to fill up content when it needs to, maybe never
--
Besides my dubious efforts, there is a much better version of viols (more than one) in the package
Early Music Ensemble (v3)
made by Arianna Cunningham for Musescore