A long line of Christian aspiration and endeavour culminates in the "St. Matthew Passion" music. The Good Friday service, or mystery, of the Passion dates back to mediæval times. Musical settings of it are quite innumerable. They fall into three main groups, according to style. The earliest are in the "Plain-song" of the mediæval church. At the period of Luther's Reformation the plain song gave way to the chorale style. Finally, there are many settings in the oratorio style. Of these Bach himself certainly wrote four, and probably five. By universal consent the "St. Matthew Passion" is the finest of Bach's settings. The main outlines of the scheme were fixed by tradition. Bach had the assistance of a poet named Picander in arranging his text, but it was by Bach's own judgment that all important points were settled. He divided the story into two parts. The first comprises the conspiracy of the High Priest and Scribes, the anointing of Christ, the institution of the Lord's supper, the prayer on the Mount of Olives and the betrayal of Judas, and ends with the flight of the disciples. In the second part are set forth the hearing before Caiaphas, Peter's denial, the judgment of Pilate, the death of Judas, the progress to Golgotha, the Crucifixion, Death and Burial of Christ. Between the two parts there is a broad contrast, a certain solemn stillness prevailing in the first and a passionate stir in the second. Fifteen chorales are heard in the course of the work, each forming a meditation upon the foregoing incident in the story. The chorus is double, and there is immense power in the manner in which the two main masses of sound are used, both to emphasise all that has poetic value and to express the many elements composing the mighty picture. Most of the solos are supported by the first choir. The utterances of Christ are given by a bass voice with string quartet accompaniment. The bass voice is in accordance with tradition. Most of the other recitatives have an _obbligato_ accompaniment, in which a _motif_ bearing figurative reference to some prominent image in the text is worked out. The _obbligato_ is in most, though not in all, cases assigned to a wind instrument, so as to contrast still further with the music accompanying the words of Christ. The longest solo part is that of the Narrator, who sings tenor. In the course of a long and masterly discussion Dr. Spitta, the great biographer of Bach, contends that the "St. Matthew Passion" is not, strictly speaking, either dramatic music or oratorio music. One passage in the discussion may here be quoted:--"Consider the passage where the Jewish people, prompted by the High Priests and Elders, demand the release of Barabbas. The Evangelist makes them reply to Pilate's question with the single word 'Barabbas.' The situation is, no doubt, full of emotion, and an oratorio writer might have let the tension of the moment discharge itself in a chorus.