The 13-course lute was the last type of mainstream lute before the instrument's gradual decline towards the end of the 18th century. It was developed in Germany around 1720 and would have been the type of lute known to J.S. Bach. There were two types of 13-course lutes and mine is of the kind where the first pegbox is extended to a second pegbox to allow for longer bass strings. This gives a stronger and richer sound to the bass, which is required by the German music of the mid 18th century. The back of my lute is made of rosewood.