Although much of his chamber music was published, C P E Bachs fame depended more on his solo keyboard music and especially his instruction book on harpsichord-playing, Versuch über die wahre Art das Clavier zu spielen
(Essay on the true art of playing the keyboard), published in 1753. In many respects, the move to Hamburg caused a significant change in his output, and he concentrated particularly on church music. But he continued to write for the keyboard, especially for the clavichord, for which he produced music of a great emotional intensity. The dance La Folia
was first noted two centuries earlier in Spain, and became popular in Italy earlier in the seventeenth century. Eighteenth-century composers knew it chiefly from Corellis variations for violin and continuo (Op 5 No 12), and its chord sequence became a frequent basis for similar treatment. Bachs variations, written in 1776, are alternately expressive and virtuosic.
from notes by Clifford Bartlett © 1988