"The griffin, a modern hieroglyphic, signifying strength and swiftness, united in the two noble forms of the lion and eagle, is a grand object. So the antique centaur hath a savage greatness as well  as beauty.

    These may be said to be monsters, it's true, but then they convey such noble ideas, and have such elegance in their forms as greatly compensates for their being unnaturally join'd together.

     I shall mention but one more instance of this sort, and that the most extraordinary of all, which is an infant's head of about two years old, with a pair of duck's-wings placed under its chin, supposed always to be flying about, and singing psalms.

     A painters representation of heaven would be nothing without swarms of these little inconsistent objects, flying about, or perching on the clouds; and yet there is something so agreeable in their form, that the eye is reconciled and overlooks the absurdity, and we find them in the carving and painting of almost every church. St. Paul's is full of them."

This is from William Hogarth's book The Analysis of  Beauty.