Most baroque violinists in the 21st century who perform historical repertoire are accustomed to performing at a range of pitches, and in a variety of temperaments. These pitches and temperaments are determined by current understanding of those that were being used at particular times during the Baroque era, or at other times in the past including in the Renaissance, Classical, and Romantic eras. This understanding is based on surviving historical instruments and descriptions in historical documents about performance pitches and temperaments (Barbour, 2004; Duffin, 2007, Haynes, 2002).