"The ancients knew these powers so well, that, while concealing their true nature under various allegories, for the benefit (or to the detriment) of the uneducated rabble, they never departed from the multiple object in view, while inverting them. They contrived to throw a thick veil over the nucleus of truth concealed by the symbol, but they ever tried to preserve the latter as a record for future generations, sufficiently transparent to allow their wise men to discern that truth behind the fabulous form of the glyph or allegory. They are accused of superstition and credulity, those ancient sages; and this by those very nations, which, learned in all the modern arts and sciences, cultured and wise in their generation, accept to this day as their one living and infinite God, the anthropomorphic 'Jehovah' of the Jews." ―H.P. Blavatsky, The Secret Doctrine, Volume I, iv. “The Four Elements

Art is an expression of consciousness; therefore the level of being of an artist is expressed through his or her work.  The great artists of humanity have always been profound mystics and apostles who taught how to unite with divinity through their music, writings, and paintings.  Unlike modern art that is divorced from spiritual principles, ancient and classical forms of art embody the highest ideals attainable by mankind, and only those who awaken consciousness can recognize such divine principles within great literature, sculptures, etc.  The mystery schools of Universal Gnosticism disseminated their secret knowledge through the veils of allegory, symbolism, and artistic mediums, so as to evade persecution and provide their knowledge to other initiates without openly giving away their secrets.

Learn how esoteric mysticism, science, and philosophy were taught within ancient art forms: sculpture, poetry, drama, theater, opera, classical music, and more. This lecture explains hidden teachings given by Beethoven, Mozart, Wagner, and other classical composers, as well as through the mystical dances of the Sufis, the architecture of the Egyptians and Mayans, and more.

Resources and References:

http://chicagognosis.org/lectures/fundamentals-of-gnostic-art