The Golden Age Greeks wrote of the Muses. Credited with being the source of all art and engineering.
To look upon the gods directly caused madness. It still does. The Muses were intermediate spirits, that only made people partly mad, for a while.
Being with your Muse was described, people got such a strong idea that they did not respond to the world, eat, sleep, bathe, as they worked with all their energy on something, till they fell into sleep, still dressed, then awoke to start again. This continued till they were done, at which point they became people again. It was advised to just leave food and drink near, not to speak to them, for the gifts of the gods were to be honored.
The Greeks said everything of great perfection came this way. All of the Epic works. The Muses chose few, and those without were pitied, they could do ordinary work, but great works took having a Muse.
The Muses were named for the gifts they brought, song, poetry, music, seven in all I think. Wiki your Muse.
As a group they were Deamons, less than gods, more than men. Having one was considered the greatest gift of the gods, to be chosen to bring knowledge and beauty into the world.
I see a lot of autism in the description, and wonder at the Greeks who were wise enough to look at the gifts, and accept the people who brought them.
In fact, it was also an honor to be their Patron, to protect and care for those the gods had chosen. It was considered a joint venture with the gods, supporting their work on earth. Hence, a very high form of worship.
According to the Greeks this system worked well. Everyone shared in the gifts, the person with a Muse was cared for, for they were reused by the gods and needed to be kept in good shape between obsessions, when they were just ordinary people. If you knew, you could tell they had been touched by the gods, for they did have some traits that only they shared. They talked to the unseen when alone.
Mostly they were common people, good only at one thing, but very good at that, and another thing was, the doors of the richest and most powerful were always open to them, for they brought messages that should be heard. They were always first to bring forth the new ideas.
From the gods, through the Muses, to who they chose, then to men. Wise men listened, for this fool speaks the message of the gods.