What a nice name: Viola d’Amore.
Description from the Metropolitan Museum of Art:
The instrument represents the early form of the viola d’amore, which was strung already with metal strings but not yet with sympathetic strings. The oldest written evidence for the early viola d’amore is a remark by the English diarist John Evelyn, who in 1679 called it a new instrument, strung with five metal strings and “sweet” in its sound. The early viola d’amore was not standardized in form or in number of strings and tuning. Three other instruments of the same festoon shape survive from Grancino’s workshop, but each is a somewhat different size and has a different numbers of strings. The only instrument with its original neck has four strings, two others have five, and this one has been restored—apparently correctly—with six strings. Grancino is often considered the most renowned maker of his generation outside Cremona.
Sketch 064: Viola d’Amore by Giovanni Grancino, Metropolitan Museum of Art, Purchase, Amati Gifts, 2008