This quadrant was made by Carlo Renaldini, an active member of the Accademia del Cimento. The instrument was used for astronomical observations and measurements. Its wooden structure was built by Anton Francesco Tofani in 1667. The mathematical divisions were placed by Jacopo Mariani in 1684. The original index (rule) is now lost. There is a magnetic compass resting on a small head. The quadrant bears a dedication to Prince Leopold de' Medici.