The Organistrum was a stringed instrument of the period. Medieval musical instruments such as a fiddle or vielle were used as model. The proportions were increased for the convenience of holding the instrument and of dividing the performance between two persons. Inside the body of the organistrum was the wheel, having a tire of well greased leather and working easily through an aperture in the sound-board. The three strings rested on the wheel which were supported on a bridge of the same height.

Family of Instruments: The Organistrum belongs to the family of String instruments.