According to excellent authority, Bach wrote five complete "year books" of church cantatas. Reckoned according to the requirements of the Leipsic church year, they would therefore reach a total of about four hundred, but not more than half that number have been preserved. The name here employed was given to the works in the present century; Bach himself called them concertos, and thereby indicates their historical origin. The sacred concerto was first introduced into Germany by Schütz, who imported it from Italy. Originally a piece of one or more solo parts with an instrumental accompaniment pervaded by intense passionate feeling, it soon adopted the chorus as a means of attaining completeness and variety. The choral, elaborated in various ways was then added and afterwards the aria in its different forms, the text of this new style of concerto being expanded to correspond. While in the beginning this text consisted only of biblical passages or prayers, all kinds of devotional poetry were later employed, in connection with the choral stanzas. After the year 1700 the so-called "madrigal" form of poetry found its way into the concerto and was also very commonly made use of in operatic music. In this way the recitative became a part of the concerto, which had gradually been made to include all the vocal forms then in vogue. The church cantata of Bach is the sacred concerto, in its most perfect form. As a means of blending into a harmonious whole the manifold elements which composed it, Bach had recourse to the style of his organ music, as carefully wrought out by him in the bosom of the church. In this way, while implanting upon the work all the forms which have been enumerated, he imparted to it the truly ecclesiastical character which it had never before possessed. The choral now became the principal musical feature of the concerto (or cantata) and the closest connection was established between the text of the work and the Bible selection which formed the subject of the sermon on the particular Sunday or festival day for which it was composed. The regularly appointed place for the cantata in the church service was just before the sermon, but, on very important occasions, it was sometimes divided into two parts, the second of which came after the sermon. The wealth of creative power revealed by Bach in this musical form, which now unhappily has become unfamiliar to us, transports one with astonishment; above all, his treatment of the choral is simply amazing. Appearing in solo and chorus songs, artistically elaborated or in simple popular form, resounding in a single instrument or in a group of instruments, while the singing voices are occupied with another text, which seems to receive its highest consecration from this interpenetrating melody, it imparts strength and animation to the entire work, and in proportion as Bach advanced in years, he gave greater definiteness to this central feature of the cantata. The texts for such