Note 321 — Chapter XV · THE EMPIRE AS AN INTERNATIONAL POWER.
Reading edition
There is a curious seal of the Emperor Otto IV (figured in J. M. Heineccius, De veteribus Germanorum atque aliarum nationum sigillis), on which the sun and moon are represented over the head of the Emperor. Heineccius says he cannot explain it, but there seems to be no reason why we should not take the device as typifying the accord of the spiritual and temporal powers which was brought about at the accession of Otto, the Guelfic leader, and the favoured candidate of Pope Innocent III.
The analogy between the lights of heaven and the princes of earth is one which mediæval writers are very fond of. It seems to have originated with Gregory VII.