A bowed version of spanish vihuela also called "bowed viola" or even "fídula".

Wikipedia: "The vihuela is a 15th-century fretted plucked Spanish string instrument, shaped like a guitar (figure-of-eight form offering strength and portability) but tuned like a lute. It was used in 15th- and 16th-century Spain as the equivalent of the lute in Italy and has a large resultant repertory. There were usually five or six doubled strings."

More info: Vihuela de arco (in English)