"The Great Silence" looks to have Theosophical and Rosicrucian origins. Those movements probably took the phrase from earlier teachings.
1890 [books.google.com]
2014 [books.google.com]
Quote
He who steadfastly progresses towards the Great Solitude, the Great Silence, does not see in anything that helps him thither either dreariness or monotony.
1890 [books.google.com]
Quote
there is the "Great Silence", where all the world seems to disappear
2014 [books.google.com]