Biber's famed sonatas, often called either the "Mystery" or "Rosary" sonatas, may have been composed for the formation of a Rosary Confraternity. This institution consisted of a group of prominent citizens would get together to pray the rosary and also, most likely, socialize and talk local politics. The sonatas were never published, indicating their eccentricity, difficulty, and unsuitability for the mass market. While they would have been performed on a standard instrument of the period, fourteen of the sixteen sonatas also use a technique known as "scordatura," in which the strings are re-tuned to unusual combination to achieve particular colors and facilitate the playing of certain chords. Each sonata is programmatic and accompanied by an engraving depicting a "mystery" or biblical story for the purpose of meditation.