I was in Rome for research for my Medieval thriller Murder in Rome, starring Bulgarian Orthodox priest, archivist and detective Petar Ivanov. The Bulgarian ambassador is killed in 1240 AD.  

The Bulgarian Emperor Plamen VI sends father Petar and his assistant deacon Alexander Nemev to catch the killer. Pope Gregory IX is supposed to assist the clergymen, but he is very busy in his power struggle with German Emperor Frederick II. Can the Bulgarians find the killer? 

I do admit that Rome is word famous. Sofia not quite so. The Bulgarian capital has about two million people, the Italian capital is about twice that size. Sofia was called “Serdica” in Roman times.