The Probert Encyclopaedia of Music

DOUBLE-BASS

The double-bass or violone is the largest instrument of the bass-viol kind, having three or four strings tuned an octave below those of the violoncello, and traditionally played with a bow. The double-bass was probably invented by Gaspar di Salo in 1580, and was a particular feature of certain 1950s Rock and Roll bands, who plucked it rather than played it with a bow.
Research Double-Bass