Richard de Monbasto, The Martyrdom of St. Hippolytus
Bibliothèque Nationale de France, MS. Richelieu MSS. Fr. 185
In this image horses pull the saint's body apart, as is recounted in some versions of his vita. Others, including the Golden Legend, say horses dragged him through rough terrain until he died.
Read more about images of St. Hippolytus.
Source: this page at Wikimedia Commons.