This is the non definitive list of the historical
DOUBLE BASS and VIOLONE in our Collection:

 

ITALY

Violone in G, 6 strings, Milano School , 18^th C. (#73)

Violone in D, 6 strings, Venetian, 17^th C. (#70)

HABSBURG EMPIRE

Johann Georg Thir, 5 strings, Vienna, 1750 (#71)

Johannes Udalricus Eberle, 4 strings, Prague, 18th C.  (#72)