Nessus the centaur was killed by Hercules for attempting to rape his bride Dejanira. Before dying, Nessus gave Dejanira his bloody tunic, telling her to give it to Hercules if he was unfaithful, and his affections would return. When she did this the shirt stuck to Hercules\' skin and he burned to death in agony. Ovid, \'Metamorphoses\' (Book IX). The picture may have been part of a decorative scheme, illustrating the life of Hercules or stories of thwarted love. It dates from around 1700.