Worshippers offer sacrifice to a statue of Pan, god of the wilderness and fertility. The subject is taken from Antiquity, but many details - the Chinese porcelain and exotic clothing - are strangely out of place. The effect is fantastical and different from the archaeologically accurate paintings of some of his contemporaries. Inspired by Flemish art, Castiglione fused careful description of the material world with a painterly touch - the obvious movement of the artist's brush makes us aware of how it was painted as much as what is shown. The artist rapidly sketched out the composition in black paint which has become visible with age. At left, his first thoughts for a tree, later rejected, can be seen. Other effects of aging have altered the balance of colour; green leaves have become brown, as often seen in Old Master paintings. In contrast, the blue of the distant mountains and the man's robe remains startlingly vibrant.