The task of seventeenth century musicians was, then, in large part, the establishment of tonality and the hierarchy of keys, contrasted with one another, but accessible by modulation; the crystallization, by means of both harmonic and metrical definition, of individual themes out of the amorphous tonal matrix of previous eras, and the exploration of means for building up these themes into coherent organisms; and lastly the emancipation of the art thus brought into full life from the tyranny of association with words and voices. This was an immense task; and it is not to be wondered at that most of the men engaged in it never attained mastery enough to give them great personal prominence. Theirs was a time of beginnings, of preparation for novel and unprecedented achievements. The early opera-writers, the Italian violinists, the German organists, and the clavichord and harpsichord writers of that period, men like Cavaliere and Caccini, Corelli and Scarlatti, Sweelinck and Frescobaldi, Purcell, Kuhnau, and Couperin, are chiefly known to us as preparers of the soil, and sowers of the seed, for a harvest which was gathered by later, and probably greater, though not more honorable men. The first composer after Palestrina who like him overtopped all his fellows, and brought to its culmination another great period, was Johann Sebastian Bach. In Bach’s style we find, in addition to the polyphonic or many-voiced texture of Palestrina, a thematic pointedness and logic and a harmonic structure which are entirely unforeshadowed in the older man. The fugue, a form which he carried to its highest pitch, and which was admirably suited to his genius, is in certain respects allied to the earlier style, though in others wholly modern. Like the ecclesiastical forms of Palestrina, it is of the basket-work type of texture. One voice begins alone, others enter in succession, and all wind in and out amongst one another almost as intricately as in a sixteenth century madrigal. On the other hand, the fugue as a whole begins and ends in some one key, and throughout its progress modulates from key to key with well-planned contrasts and firmly-controlled movement. Moreover, a single definite theme or subject appears at the outset of the piece, and stands prominently forth through its whole extent; it is announced by the first voice, repeated at a different pitch in the answer of the second, reiterated again by the third and fourth, and subsequently made the basis of an ingenious, varied, and extended development. Finally, although some of Bach’s fugues are vocal, most of them are written either for organ or for clavichord. In all these respects his work is modern, and perhaps most of all is it modern in its inexorable logic, its subtlety and variety, and in its poignant, deeply emotional expressiveness, which is always held within the bounds necessary to supreme architectural beauty. The period of Bach and his precursors,