Rubsam Naxos

The six Trio Sonatas for organ seem to belong to the earlier years of Bach's period in Leipzig, dated conjecturally to 1727, apparently devised for the use of the composer's eldest son Wilhelm Friedemann, who became one of the most distinguished organists of his generation in Germany. The sonatas demand clarity of performance and distinct enunciation of the two melodic lines and bass pedal part.

The fugue of the mature Baroque was the final flowering of Renaissance and Baroque polyphony. While most composers of Bach's generation had turned to other musical forms, Bach himself continued to write in "older" styles, and was to become the unchallenged master of the fugue. Die Kunst der Fuge was written during the last years of his life, and was being prepared for publication at the time of his death.

The works collected and revised by Bach probably between 1744 and 1747 and included in the so-called Leipzig Autograph, the Leipziger Originalhandschrift, were largely composed between 1708 and 1717, the years spent in Weimar. The chorale, the congregational hymn of the German Protestant church, had its roots in pre-Reformation practices. Its importance in Lutheran church music may in some respects be compared with the importance in Catholic tradition of plainchant, itself a source for some chorale melodies. As in other fields of music, Bach's varied treatment of the chorale sums up and crowns a long tradition.

The Organ Mass continues with the Our Father, Vater unser im Himmelreich (Our Father in Heaven). Here a much ornamented subject appears immediately in the upper part, to be imitated by the second voice. The chorale melody itself is presented in canon between the upper part and the fourth of the five voices. There is a shorter alternative working of the Vater unser, for manuals, its melody in the upper part.

Nun komm, der Heiden Heiland (Now come, Saviour of the Heathen) appears in three versions. The chorale on which it is based is Martin Luther's adaptation of the original Ambrosian hymn Veni Redemptor gentium. The first of these, for two manuals and pedals, opens with the first measures of the chorale theme in the tenor, imitated at once in the alto register, over a constantly moving pedal bass. The melody is then elaborated in the upper part to form an ornamented line.

During his years at Weimar Bach made a number of keyboard arrangements of concertos and instrumental movements by other composers. His arrangements of concertos by Vivaldi, six of them for harpsichord and three for organ, remind us of the strong influence Vivaldi exercised over Bach's Instrumental compositions. The sixteen arrangements for harpsichord include a keyboard version of an oboe concerto by Alessandro Marcello, a violin concerto by Telemann and three concertos by Prince Johann Ernst of Saxe-Weimar. The six concertos transcribed for organ also include arrangements of two concertos by Duke Johann Ernst. The latter was a nephew of Bach's employer and a pupil for keyboard and for composition of Johann Gottfried Walther, organist of the Weimar Stadtkirche. His principal instrument was the violin and Telemann wrote for him a set of six sonatas for violin and clavier. Johann Ernst died in 1715 at the age of nineteen, leaving nineteen instrumental works. Of these six concertos were published posthumously by Telemann in 1718.

The third volume of the Clavierübung, a collection of various chorale preludes described as on the catechism and other songs, was assembled in 1739 in Leipzig. Known as the Organ Mass, corresponding as it does, in part, to the movements of the Mass, the work is framed by the Prelude and Fugue in E flat major, BWV 552, the fugue known to English audiences as the St. Anne Fugue, because of the resemblance of the opening of the fugal subject to the well known Croft hymn-tune of that name usually coupled with the words O God, our help in ages past. The dotted rhythms of the Prelude make an impressive opening, with its concerto grosso contrasts of dynamics.