The Elixir of Death — Bernard Knight

1195. Prince John still plots to seize the throne from his brother, Richard the Lionheart--and in his wicked schemes he is supported by Philip of France. The French king offers to help John financially by sending him a mysterious alchemist, a Mohammedan named Nizam, who claims to be able to turn base metals into gold.

But the ship which was transporting Nizam and his retainers is found wrecked off the south Devon coast, its crew savagely slaughtered. Shortly afterwards, a Norman knight named Peter le Calve is foully murdered, his severed head stuck on the rood screen of Exeter cathedral.

It's up to Sir John de Wolfe, the county coroner, to find a motive and connection between the killings. And just what is his unscrupulous brother-in-law, the disgraced ex-sheriff and Prince John-sympathizer, Richard de Revelle, trying to hide?