Arthur Machen 
Three Impostors, or, The Transmutation 

The Three Impostors; or, The Transmutations is an episodic horror novel by British writer Arthur Machen. The novel comprises several weird tales and culminates in a denouement of deadly horror, connected with a secret society devoted to debauched pagan rites. The three impostors of the title are members of this society who weave a web of deception in the streets of London-relating the aforementioned weird tales in the process-as they search for a missing Roman coin commemorating an infamous orgy by the Emperor Tiberius and close in on their prey: "the young man with spectacles".