Six course mandolins are a type instrument of the mandolin family which was born in northern Italy, in particular near Milan, during the 18th century. They initially only had four courses, then a fifth one was added, and then a sixth. It was with the sixth course added that the evolution of the instrument and its repertoire stabilized during the entirety of the century.
These mandolins are quite different from the modern neapolitan mandolin: they have features such as a flat top, glued bridge, a very light structure, gut strings, tuning by fourths and thirds. These are just some of their peculiarities, which make them unique and irreplaceable instruments in the historic musical rendition of its repertoire, which includes Vivaldi and the theaters of the 18th century.