I'm currently reading on the evolution of spirituality in the arts, triggered by an inspiration from learning more about Hilma af Klint (one of whose paintings is on the cover of probably the most important all-time books for me, Ken Wilber's Sex, Ecology and Spirituality). It's a fascinating journey across realms such as Theosophy, that rewrites in many ways art history (which Hilma af Klint's story illustrates perfectly, her only recently being recognised as the true pioneer of abstract art before Kandinsky) and a new interpretation of modern art.
The evocation of spirit guides has a prominent place in this narrative that transcends the boundaries of religions, and spiritual traditions. But were these artists reaching to a particular god, God or deity / deities?
In my research, the first identification of the common intellectual recognition of the common wisdom foundations across religious traditions came from the intellectual community associated to the The Great Library of Alexandria in Alexandria, Egypt (est. ~250BC - 270AD), was one of the largest and most significant libraries of the ancient world. The Library was part of a larger research institution called the Mouseion, which was dedicated to the Muses, the nine goddesses of the arts.