The technical history of modern harmony is a history of growth of toleration by the human ear of chords that at first sounded discordant and senseless to the main body of contemporary professional musicians.
Rhythm and harmony enter most powerfully into the inner most part of the soul and lay forcible hands upon it, bearing grace with them, so making graceful him who is rightly trained.
You would never hear any song played twice in the same way. The words were retained, but within a certain frame there was great latitude, and the musician could improvise to his heart's content; and the more the variations and combinations, the greater the musician.