Viola d'amore, Austria, 1719 ca.

 http://collections.vam.ac.uk/item/O58927/viola-damore-unknown/

The viola d'amore was particularly popular throughout Italy and Central Europe during the 17th and 18th centuries, and was noted for its sweet tone. Seven gut strings were played by the bow, while seven 'sympathetic' strings placed underneath the fingerboard responded to the resulting vibrations. This instrument bears the coat of arms of Franz Anton Graf von Harrach, Prince Bishop of Salzburg between 1709 and 1727. German and Austrian noblemen had their own private orchestras, and this instrument would probably have been used by one of his musicians.