It was on the island of Patmos that Saint John wrote the Book of Revelation. Beside him rests his symbol, the eagle, which holds the saint's ink pot. In the sky above is a vision of a woman and child ('the Woman clothed with the Sun') and the seven-headed dragon of the Apocalypse. On the ground near John is a small devil monster who seems to be attempting to prevent him from writing.
The landscape is in the style of Patinir, but both the landscape and figure are consistent with the work of the Master of the Female Half-Lengths, including the painting after whom the artist is named.