The Great Eighteen Chorale Preludes, BWV 651–668, are a set of chorale preludes for organ prepared by Johann Sebastian Bach in Leipzig in his final decade (1740–1750), from earlier works composed in Weimar, where he was court organist. The works form an encyclopedic collection of large-scale chorale preludes, in a variety of styles harking back to the previous century, that Bach gradually perfected during his career. Together with the Orgelbüchlein, the Schübler Chorales, the third book of the Clavier-Übung and the Canonic Variations, they represent the summit of Bach's sacred music for solo organ.

Leonora Duarte (1610 – 1678?) was a Baroque Flemish composer and musician, born in Antwerp. She belonged to a wealthy Portuguese-Jewish family who were major patrons of the arts and music. She was baptized on 28 July 1610. Duarte composed seven sinfonias which are the only known pieces of music written for viol by a woman in the 17th century.