There once was a wealthy Roman man named Vedius Pollio, infamous for maintaining a reservoir of man-eating eels, into which he would throw any slaves who displeased him, resulting in their gruesome deaths. When Emperor Augustus dined with him on one memorable occasion, a servant broke a crystal goblet, and an enraged Vedius ordered the servant thrown to the eels. Augustus was shocked and ordered all the crystal at the table to be broken. Vedius was forced to pardon the servant, since he could hardly punish him for breaking one goblet when Augustus had broken so many more.

That servant seems to have been spared, but many others had their "bowels torn asunder" by the eels. And that's just one of the many horrific ways the ancient Romans devised to kill those who displeased or offended them, from crucifixions and feeding people to wild beasts, to setting slaves on fire, and assassinating Julius Caesar on the Ides of March. Historian Emma Southon covers them all in her wittily irreverent new book, A Fatal Thing Happened on the Way to the Forum: Murder in Ancient Rome, showing us how the people of ancient Rome viewed life, death, and what it means to be human.

Inspiration struck in April 2018, when the notorious Golden State Killer, Joseph James DeAngelo, was arrested—a big day for true-crime aficionados like Southon. While chatting with a fellow true-crime buff and history teacher, Southon learned that her friend often used true crime as a teaching tool for specific cultural biases—for instance, using the example of Jeffrey Dahmer as a context for discussing homophobia in the 1990s. Intrigued, Southon searched for a true-crime book about killings in ancient Rome only to realize that nobody had written such a book. So she set out to rectify that grievous oversight, and the result is a delightful blend of true crime and ancient history.

Southon was struck by the elaborate nature of the public executions in particular. "Just having someone being eaten by a leopard wasn't fun enough [for the Romans]," she told Ars. "They had to find ways to build narrative tension: when is it going to happen? Where is the lion going to come from?" Crucifixions occurred in the most public spaces, and the Romans presumably were inured to the sight of rotting bodies falling apart on a cross as they went about their daily activities. "Just like true crime, it's the horror that makes it fascinating," Southon said. "You just want to poke at the dark soul behind it and see what makes that tick."

Ars sat down with Southon to learn more.

Ars Technica: You spend a lot of time at first talking about the definition of murder. How did you determine what constituted murder in ancient Rome for inclusion in your book?

Emma Southon: Murder is very culturally specific. It's not that easily defined. Homicide is easily defined and has a clear definition: when one person kills another person. Murder is a word for something that is a crime, and that is different from homicide. English law is very specific. American law, because it's so many different states, it's wild. There's so many different ways in which murder is defined: you have first-degree murder and second-degree murder, and then manslaughter, and then first-degree manslaughter and second-degree manslaughter. It's so broad, and yet so specific at the same time, but if you move 10 miles in any direction, it's a completely different thing. So I could just say, "I'm just counting all homicide as coming under the umbrella of the book," even though the Romans would never consider any of this murder. It's an emotive topic, and law is often much more emotive than people think it is.

Ars Technica: Did the Romans even have a legal concept of murder?

Emma Southon: They did, but it was very specific about the methods used: poisoning, or carrying a knife. But if you threw somebody off a cliff, that doesn't fall under that law. Much later on you get things like Constantine's law, the first one that outlaws killing enslaved people. He lists, for about a page, all of the ways in which you're no longer allowed to deliberately kill an enslaved person. "Don't set them on fire. Don't throw them off of something. Don't hit them with a rock. “Why do you need to be this specific? It's because Roman laws are so often not aiming at generic things. They are responding to something specific. Especially when you get to the Imperial period, they are generally propagated in order to respond to a specific problem, rather than trying to make a law that is applicable to lots of things.