There are isolated instances of deeper sentiment and more poetic conception which are heightened in effect by the earnest technical skill displayed in their working-out, and which give glimpses of happy inspiration, not belonging of necessity to the fundamental conception of the work. Unhappily it is on these masses, in the composition of which Mozart's genius could only move within very confined limits, that his fame as a composer of church music chiefly rests; and musicians who have taken him as their model have striven most to imitate these, his least satisfactory works. The great resemblance in plan and mechanism of the masses of contemporary composers, such as Hasse, Nau-mann, Joseph and Michael Haydn, proves a strict adherence to the rules of composition then in force. A consideration of their works serves to heighten the effect of Mozart's higher and nobler conceptions, of his poetical sentiment, and of that sense of proportion which regards a work of art as a whole, and recognises the limits imposed on it from without as the necessary conditions of artistic production. Many excellent qualities may be conceded to these musicians, but none of them attained to the harmonious beauty of Mozart. {CIRCUMSTANCES AFFECTING CHURCH MUSIC.} (265) The artists of a later age, who imitated and exaggerated the cramped and obsolete forms, which had been the result of many circumstances, as if they were in themselves an all-sufficient musical method, judged Mozart's works by their own standard, and found them in many respects unsatisfactory.[31] Before condemning Mozart's readiness to adapt his compositions to external conditions, we must consider the mode of thought of the time. All art, more especially music, stood in the closest connection with the ordinary affairs of life; operas, masses, instrumental works were composed when, where, and how they were required, for particular occasions, and particular performers. Occasions of the kind were eagerly sought for, and furnished an impulse and incitement to the composer, even when they somewhat hampered his productive powers. Exaggerated as the reference to external circumstances and mechanical resources became, it formed the groundwork, rightly understood, of thorough artistic production.