During the first half of the period in which Bach resided at Weimar, occupying the position of court and chamber musician to Duke Wilhelm Ernst, he wrote three cantatas in the old church form which are notable as being the last he composed before adopting the newer style, and as the most perfect of that kind extant. The first of these, "Nach dir, Herr, verlanget mich," is based upon the first two verses of the Twenty-fifth Psalm. The second, "Aus der Tiefe rufe ich," includes the whole of the One hundred and thirtieth Psalm and two verses of the hymn "Herr Jesu Christ, du höchstes Gut." The third and most famous of the trio, "Gottes Zeit ist die allerbeste Zeit" ("God's time is the best of all"), is generally known as the "Actus Tragicus," and sometimes as the "Mourning Cantata." Of its origin Spitta says:-- "Judging by its contents it was designed for the mourning for some man, probably of advanced age, to whom the song of Simeon could be suitably applied. No such death took place in the ducal house at this time, for Prince Johann Ernst died when a youth, and also when Bach's style of composition had reached a different stage. Possibly the cantata has reference to Magister Philipp Grossgebauer, the rector of the Weimar school before its reorganization, who died in 1711; at least, I can find no other suitable occasion. The contrast between the spirit of the Old and New Testaments,--between the wrath of an avenging God and the atoning love of Christ,--which had already appeared in the One hundred and thirtieth Psalm, is the germ and root of this cantata to such a degree that it is evident that Bach had fully realized by this time how fertile a subject for treatment it was. It contains no chorus of such depth and force as those of the One hundred and thirtieth Psalm. Its character is much more entirely individual and personal, and so it has a depth and intensity of expression which reach the extreme limits of possibility of representation by music. The arrangement of the poetic material is most excellent; it does not wholly consist of Scripture texts and verses of hymns; and in several fit and expressive thoughts, which are freely interspersed, we can almost recognize Bach's own hand. If such be the case, the whole arrangement of the poetry may with reason be ascribed to him."