Among the many intriguing first-century locations where Rubies of the Viper takes place—Nero’s sumptuous palace, Theodosia’s Villa Varroniana, an Etruscan necropolis, and others—none fascinated me more as I was writing than the infamous slum known as Subura.

The area known as Subura, a notorious part of the ancient city of Rome, was originally a swamp lying between the Viminal Hill and the Esquiline Hill. Sometime around 600 B.C., the Cloaca Maxima (“Greatest Sewer”) was built through the area to serve the twin purposes of carrying human waste to the Tiber River and draining the swamp for development. As one might expect, given the technology of 600 B.C., the drainage wasn’t perfect, so Subura remained an unsanitary, mosquito-infested, disease-ridden place to live.

At first, it was the home of respectable citizens, including the family of Gaius Julius Caesar. Single-family houses were the norm, as were prosperous shops. It was also the site of an early Jewish synagogue.

Over time, as hordes of foreigners, landless former farmers (see Gigantic Estates), and impoverished ex-slaves poured into the city looking for work, Subura turned into a noisy, dirty, and wet dumping ground for the dregs of society. There was no law enforcement. No social order. No sanitation. No safety net. Prostitutes, pimps, and pickpockets flourished. Tiny shops built into the walls of houses offered fish, eggs, cabbages, bread, and other cheap provisions. Barbers, cobblers, and peddlers of tinware and fabrics cluttered the narrow streets.

In a first-century version of “white flight,” prosperous Romans literally headed for the hills, two of which—the Caelian and the Palatine—would forever after be enclaves of wealth and nobility.

Here’s how a Rubies of the Viper reader experiences Subura on Theodosia’s first visit back there after spending months in her luxurious coastal villa:

Overhead loomed the wooden firetraps where thousands of Rome’s poorest, mostly foreigners and former slaves, found crude shelter but little else. So tall and tightly packed were the buildings that the sun made its way to the streets for only a few hours a day. An open window on the top storey of one building belched the sounds of a ferocious argument. Balcony-hung laundry—flapping and snapping in the breeze—formed a counterpoint to the slaps and curses and breaking pottery.

Nor was life any more pleasant on the ground. A pack of feral dogs—nosing through the offal and creating more—snarled if anyone came too close. Four naked toddlers played unattended in the dirt. A trio of drunks quarreled in a corner bar. The streets stank of urine, sewage, and rotting garbage.

Theodosia’s house stood in a slightly better neighborhood in the heart of Subura, where people owned their single-storey homes and attached street-side shops. Buildings were lower, so there was more sunlight. At one time, the entire area had been like this, but the surrounding blocks had been razed over the years to pack in more cheap housing.

She stopped in front of the shop where Dinos—the elderly sandal maker who was her tenant—and his slave eked out a living and slept on the floor. Dinos’ meager payments had been Theodosia’s main income for years, but she had charged him no rent since Gaius died.

Dinos was sitting on a shaded stool just inside the doorway, a bright-eyed spider alert for prey in the web of sandals spread out along the edge of the street. Now he hopped down eyes agog at the sight of Theodosia.

—text copyright © Martha Marks—