=Influence of Art on Music=.—All of the fine arts, with the exception of Music had, by the year 1100, reached a fairly high stage of development due, no doubt, to the fact that they are to a great extent composed of concrete materials. Music, owing to its lack of the concrete and the inability of men literally to place their hands upon its material, had lagged behind, so that in 1100 we find only a small amount of material, and that in a most chaotic condition. This material was, however, sufficient to produce definite musical forms if united into a homogeneous whole; such a state, however, could be produced only as the result of some great influence which would galvanize the component parts into action. Fortunately, there was just such an influence, one which had passed through an evolution similar to that needed in music, though because of its more concrete form and its necessity to man, this evolution had occurred at a proportionately earlier date. This influence was an art form, a phase of architecture known as the Gothic. Gothic architecture was a form built up by the unifying of the principal styles of architecture into one uniform whole, and composed of a _multiplicity_ of _details_, but of such evident _relation to each other_ as to make a distinct art form. This form was first used in Paris about the year 1000 A. D. Music was, approximately, in the same condition as Architecture before the birth of the Gothic principle, and needed a stimulus, a comrade art undergoing much the same evolution, to start it on its path of polyphonic development. In the year 1100 musical chaos became united into one uniform art by means of Measured Music or Proportion, thus allowing the systematizing of the mass of then existing material, and the construction of definite art forms. Since Architecture had undergone just such a change one century before, it is more than probable that the effect of this change was the starting of a similar one in Music, though the result was not to show until one hundred years after its occurrence in the kindred art.