OMNIVOROUS READER

If you believe the ancient Romans had little to do with your life, look at your feet. They gave us the concept of left and right footwear. They also left us their checkered history, of which there’s too damn much. If you’ve tackled Gibbon’s unabridged The History of the Decline and Fall of the Roman Empire, you know that a manageable history of ancient Rome requires a framing device that places events and characters in perspective.

Historian/numismatist Gareth Harney has devised an agreeable gimmick. He has selected what he believes are the 12 most significant coins minted during the Empire’s 800-plus years, and he’s written A History of Ancient Rome in Twelve Coins, connecting the coinage to the emperors and events that influenced their minting.

Roman coins were struck from alloys of gold, silver, bronze, orichalcum or copper — materials that gave them resilience — and they are discovered still in Welsh fields and Polish barnyards. You can buy a pile of uncleaned Roman coins on eBay for $30.

First introduced in the third century BCE, Roman coins were used well into the Middle Ages, and during a denarius’ existence, it would likely have passed between millions of hands. Many of the coins are worn smooth, obscuring the profile of the emperor or god whose likeness was meant to ensure political stability and economic security.

In crisp, energetic prose, Harney opens each chapter as if he were writing historical fiction. “The vision was surely his alone,” he writes of Constantine’s moment of conversion. “Yet the confused shouts of his soldiers seemed to claim otherwise. As the marching column ground to a halt before the spectacle, men raised their arms to the clear sky, calling out to their emperor to witness the unfolding miracle. It took shape, by all accounts, in the rays of the midday sun. A glowing halo surrounding the solar disk, sparkling with additional rival suns where it was intersected by radiating horizontal and vertical beams — all shimmering like jewels with spectral color.”

Harney guides the reader through the history of Rome from Romulus, suckled by a wolf on an early Roman coin, to the last emperor, who was deposed by the German general Odoacer in 476 CE. In the early years of the Empire, coins illustrated mythical scenes and various gods and goddesses, but that changed, as did much of Roman life, when Julius Caesar issued coins bearing his likeness. “Even in an age of giants — Pompey, Cicero, Antony and Cleopatra — Caesar would tower above all,” Harney writes, “bestriding the world like a colossus.” The appearance of Caesar’s profile on the Roman denarius in 44 BCE is acknowledged as a transformative moment in Roman history. The new coin violated ancient law, tradition, and the sacred delineation between military and civic authority. Caesar went so far as to order the minting of a denarius with the likeness of the defeated Gallic leader Vercingetorix, an enemy of the Roman Republic.

The Julio-Claudian dynasty receives its due — Tiberius, Caligula, Claudius, Nero, Vespasian, et al. — and Harney explains the events leading to the coinage produced by each emperor. Bits and pieces of Roman excess and debauchery are reviewed in tolerable detail, and readers are occasionally treated to new depravities, of which there was no shortage in an empire populated with leaders who were murdered almost as quickly as they took power.

For many of these upstart emperors, assassination was often a merciful escape. In 260 AD, for example, the emperor Valerian was defeated by King Shapur I and was taken prisoner. He lived out his years in slavery, falling to his hands and knees to act as a step for Shapur to mount his horse. The emperor of Rome had become a human footstool for an enemy king who later had him skinned, stuffed and placed on display.

Harney’s discussion of the various currencies makes the constant shuffling of Roman emperors slightly less confusing, but the devaluation of Roman coinage is his most significant and timely lesson. The emperors, unable to pay for Rome’s defense, lessened the amount of silver or gold in each coin. “By 270, the ‘silver’ coins of Rome held less than 2 percent precious metal. Nothing more than crude scraps of copper rushed out of the mint, without a thought of quality control. A thin silver wash on the coins only served to insult the intelligence of the Roman people, and quickly wore off to reveal the depressing base metal below.” Any belief in a reliable gold or silver standard vanished from the monetary system. As coinage ceased to hold its value, Romans returned to barter as a method of exchange. When new coins were issued, they dulled more quickly, and they felt light in the hand, signaling debasement. Each degraded coin is part of the puzzle whose final piece reveals the complete collapse of the Roman state.

A History of Ancient Rome in Twelve Coins will appeal to a broad audience. Excluding the rare reader who has a comprehensive knowledge of Roman history and the numismatist specializing in Roman coinage, the majority of readers (those who saw an episode or two of I, Claudius or the movie Gladiator) will find Harney’s history well-written, informative and sophisticated — high-end Monarch Notes for Gibbon’s six-volume Decline and Fall. They may even feel inspired to start collecting Roman coins.

Harney doesn’t claim that his research offers profound insights into our contemporary political divisions or the teetering state of our democracy, but readers will likely infer whatever lesson appeals to their politics. One truth, however, is inescapable: Empires rot from the inside out.