Painted miniature: a writer, with a castle in the background details

I suspect this is a complex emblem painting. A man with long curly hair sits barefoot on the grass, wearing a blue robe and with a red and gold cloak on his lap. He gazes heavenward for inspiration, pen poised in one hand and book in his lap. A bird stands to his left, and in his background is a castle on a cliff, overlooking the shore. An angel hovers in the sky, together with the Great Spaghetti Monster who is waving His noodly appendages.

Update: the writer shown here is Saint John the Evangelist. His symbol is an eagle (holding his inkwell), he is on an island (Patmos, where St. John was exiled), and is having his vision of the Revelation: the woman clothed with the sun, and the dragon in the sky, are visible. Thanks to Rebecca Klingbeil for the interpretation.

The image is framed as if seen through a doorway between columns.

This image was on image 14 of the Library of Congress page images.