The Misunderstood Roman Empress Who Willed Her Way to the Top

Illustrations by Romy Blümel

On the night of August 24, 410, the Roman Princess Galla Placidia was waiting for the end of the world. Although she left no record of her feelings on that fateful evening, we can recreate the scene as the 20-year-old noblewoman wandered the imperial palace complex on the Palatine Hill in the heart of the ancient city. Her surroundings exuded all the ancient splendor and confidence of the Roman Empire, the greatest the Western world had ever seen. The floors and walls of the palace were a kaleidoscope of colored marble embedded with gold and precious gems. Silver fountains burbled in the courtyards. Antique statues of military heroes and illustrious Caesars jostled with artwork and trophies brought back by the conquering legions from far-flung corners of the Mediterranean.

This was Rome, a megalopolis where glittering avenues, monuments and arches littered the landscape. A census listed 46,602 multistory tenement buildings, 1,790 palatial villas, 856 bathhouses, 28 libraries and 1,352 fountains, not to mention ten aqueducts and a sewage system. However, the city had fallen on hard times since the golden age of great emperors, like Trajan, Hadrian and Marcus Aurelius, more than two centuries earlier. Its cosmopolitan population had shrunk from one million to 600,000, and lawlessness reigned in many streets; the gladiatorial spectacles in the Colosseum were shut down in 404, leaving the chariot races as the main public entertainment. But even in decay there was no rival to Roma Aeterna, the Eternal City, Caput Mundi, the Head of the World, invincible and invulnerable … or so its citizens had believed for some 800 years.

In 410, Rome’s situation was teetering toward the unimaginable. Camped in the countryside around its titanic, marble-sheathed defensive walls was a vast army of some 100,000 warriors led by the king of the Visigoths (western Goths) named Alaric, who had marched from the Balkans under the banner of a black crow. The enemy army besieged Rome for three months, blocking its 12 gates and all transport on the Tiber River.

gold coin depicting galla placidia — A gold coin from the fifth century depicts Galla Placidia Bridgeman Images

With her classical education, Placidia would have recalled Homer’s haunting description of the Trojan army in the Iliad. The enemy campfires were so numerous, he wrote, they blazed like the stars in the night sky.

The Emperor Honorius, Placidia’s half-brother, had long since abandoned Rome to its fate. Of the imperial family, only the princess had remained, offering her regal support to the Senate as it worked to stave off disaster. Now, the city was on its knees. The population was starving. Bodies piled up in the streets. Rumors of cannibalism spread. Disease ran rampant. Many pagans blamed the Christians: Placidia’s own father, Theodosius the Great, had ordered dozens of pagan temples in the city closed, snuffed out the sacred flames of the Vestal Virgins and banned the sacrifices to the ancient gods who had protected Rome from enemy incursion for eight centuries.

Cover image of the Smithsonian Magazine January/February 2023 issue

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This article is a selection from the January/February 2023 issue of Smithsonian magazine

It was around midnight that the cataclysm began. Placidia would have heard distant sounds of Gothic horns and growing pandemonium around the Salarian Gate in the city’s northwest; not long afterward, flames could be seen rising from the nearby Gardens of Sallust. The Goths had breached the walls. The British-born monk Pelagius, who was also trapped in Rome that same night, used language that echoed the biblical vision of Judgment Day to convey the horror of the moment: “Rome, the mistress of the world, shivered, crushed with fear, at the sound of the blaring trumpets and the howling of the Goths.”

St. Jerome, when he heard the dreadful news from Roman refugees, captured the sense of shock: “It is the end of the world!” he wrote. “Words fail me; sobs prevent me from speaking. The city that once subjugated the world has been subjugated in its turn!”

Alaric, king of the Visigoths, led an army that attacked Rome, seizing its ports and gates in a monthslong campaign. Album / Alamy Stock Photo

For Romans, it was the beginning of the end. But for Placidia, it was just one more twist in an astonishing life saga that could have inspired a subplot of “Game of Thrones.” After the sack, the pampered and beautiful princess would be taken from her gilded palace as a prisoner of the Visigoths. Four years later, Placidia shocked Romans by marrying one of her captors. Then, by age 26, she was back in Italy, re-inventing herself to rule as the last empress of the Western Roman Empire.

And yet, she has been treated mercilessly by historians, who have either vilified or ignored her for most of the last 1,500 years. This has left her today all but forgotten, even though the final decades of the Western world’s most enduring empire cannot be understood without her.

Cleopatra, Joan of Arc, Catherine the Great—to the roster of history’s unfairly maligned women leaders must be added the name of Galla Placidia Augusta. Although her name in Latin means “placidity” or “peace,” Placidia’s life was anything but; she experienced more adventures than Marie Antoinette and Amelia Earhart combined. Perhaps no other figure, male or female, enjoyed such an intimate view of the Western Roman Empire’s operatic death throes or influenced events for such a prolonged period. But the attacks on her reputation began not long after her death, with authors like Cassiodorus denouncing her rule as the nadir of Rome’s fortunes. Only in recent years have scholars gone back to read the contemporary sources with more objectivity, revealing Placidia as a far more sympathetic figure, a strong-willed leader with radical ideas on how to save the crumbling empire.

It’s part of a general reassessment of her era, known as late antiquity, once dismissed as a gloomy saga of “decline and fall” to the Middle Ages, including a fresh look at so-called barbarians, who were far more sophisticated than Romans alleged.

“Placidia had an amazingly adventurous life,” explained Paola Novara, a scholar at the National Museum of Ravenna, who has written about Placidia’s legacy, including her influence on art and architecture throughout Europe. “She was a hostage for years. She was married twice, to a Gothic king, then to Rome’s most powerful general. She had one child who died, another who became emperor. She must have been a very strong and powerful character. But there has long been a negative image of Placidia,” she continued. “She was not a bad sovereign. She was brave and capable. In fact, Placidia was the last significant ruler of the Western Roman Empire. She managed it for 25 years!”

The violation of Rome in 410 would have seemed a fantastical idea to Placidia or any Roman citizen only six years earlier. On January 1, 404, the teenage princess, wearing flowing golden robes with a ceremonial headdress, had watched as Honorius staged a triumphal procession through the city’s grand avenues with his general Stilicho to celebrate their victory over the Visigoth hordes. The omens were excellent: Torrential rain the night before gave way to glorious winter sunshine, making Rome’s marble monuments sparkle as if they had been polished by a divine hand. Honorius and Stilicho rode in a chariot ahead of marching legions while throngs of citizens cheered deliriously and showered them with petals as they wound from the Forum, the city’s most ancient and revered piazza crowded with imposing temples and marble-sheathed monuments, up the steep Capitoline Hill. The future of the empire seemed assured.

The emperor at the time of the siege was Honorius, Placidia’s half-brother. Lanmas / Alamy Stock Photo

Even at this young age, Placidia had already seen more than her fair share of peril and violence. Born around 390, the daughter of a patrician named Galla and Emperor Theodosius the Great, she spent her infancy as a nobilissima puella, “most noble girl,” in the Great Palace of Constantinople in modern Istanbul, where the royal family could watch dolphins at play while being fanned with peacock feathers by eunuchs. Her father was a brilliant general but a man of extreme religious beliefs: He had changed the course of history in 380 by making Christianity the official state religion of the empire, and then in 392 he banned all other faiths entirely. The subsequent “culture war” was conducted with zeal: Fanatical Christian mobs leveled the most hallowed shrines of antiquity, including the sanctuary of Olympia in Greece, site of the Olympic Games for nearly 1,200 years, and possibly destroying the Statue of Zeus, one of the Seven Wonders of the Ancient World. Egged on by radical bishops, monastic vigilantes armed with cudgels roamed the eastern provinces burning temples and synagogues.

Around the age of 5, Placidia became an orphan, which likely honed her independence within the venomous imperial court. By age 6, she had traveled with the legions overland to Milan. She eventually moved to Rome while her teenage half-brother Honorius was elevated as emperor and moved the Western capital in 401 to Ravenna, an Adriatic port that could be more easily defended from assaults by hostile armies and usurpers.

Honorius proved to be an extravagantly incompetent ruler. He was as dimwitted as his older brother Arcadius, who was derided by critics for his “halting speech” and “drooping eyes,” and who allowed his courtiers to lead him “like an ox.” Another scathing description of Arcadius as a spineless sensualist, “living the life of a jellyfish,” could equally have applied to Honorius, whose indifference to matters of state would prove disastrous. The daily business of running the empire often fell to the many capable women in court, such as Placidia’s cousin Serena, who married the general Stilicho and managed affairs from Rome while he went on campaign after the first eruption of Alaric and his Visigoths into Italy in 401. Stilicho’s resounding victories in the next two years restored Romans’ confidence: The barbarian threat had been defused, just as it had been many times over centuries past.

The callow Honorius had never set foot on the battlefield, but he claimed the honor of a military triumph in 404 as Stilicho’s superior. The victory parade ended on the Capitoline Hill, the city’s most sacred point, presided over by the Temple of Jupiter Optimus Maximus. But in a break with tradition, the Christian Honorius declined to offer sacrifice to the king of the gods.

Although Rome’s sacred sites had been shuttered and their rites banned, many citizens remained staunchly pagan in their hearts, and their city an island of heathenism. Now, some pagans muttered in private that the offended Jupiter would withdraw his protection. Little that happened during the next six years offered proof to dissuade them.

The triumph of 404 proved to be a false dawn. From his refuge in Ravenna, Honorius hopelessly mismanaged the defense of the Western Empire. In 408, he became suspicious of Stilicho and had his most talented general arrested and beheaded. He then bungled relations with the Goths, refusing to negotiate with Alaric over his demand to help his people find food, yet failing to prepare an army to confront him. While Honorius ignored his overtures, Roman troops massacred the families of Gothic soldiers who were serving as mercenaries in the legions.

In 408, the exasperated Alaric marched across the Alps with an estimated 30,000 soldiers and 150,000 camp followers—a roving refugee nation. When Alaric blockaded Rome for the first time, the previously little-noticed Placidia revealed that she had inherited her father’s strong-willed and ruthless character. A rumor spread that her cousin Serena was plotting with the Goths. For Placidia, it was an opportunity to seize influence. She conspired with the Senate to have Serena condemned and publicly strangled, making the princess the highest-ranking imperial family member in Rome.

v2 Attack of the VIsgoth — Many within the city’s gates during the Visigoth attack surmised that the violence marked the end of the world, likening it to Armageddon. Romy Blümel

As Romans were pushed to near-starvation, the Senate paid Alaric a ransom of 42 wagons full of treasure, although the Visigoths remained in Italy. In the spring of 410, Honorius agreed to meet Alaric, but even though the Visigoth army was constantly being reinforced, soon numbering 100,000 men at arms, the Roman treated the Goth’s demands with disdain, and negotiations came to nothing. Until now, Alaric had hesitated to carry his attack on Rome to its bloody conclusion, hoping to come to a compromise. Though a Christian, he apparently also feared the wrath of Roma, the pagan goddess who personified Rome, if he were to violate her sacred city. Superstitious or not, by the summer of 410, he felt he had no choice but to attack in order to feed his horde of followers.

Nobody knows how the Visigoths managed to enter the Salarian Gate on the night of August 24. Some said it was opened from within by servants of a pious Christian noblewoman, Faltonia Proba, who wanted to end the Romans’ misery. Another possibility suggested by historians is that it was opened by rebellious slaves, who had no love for the old Roman order and preferred to take their chances with the enemy so reviled by their masters.

The next three days shook the world. The pillaging began in surprisingly orderly fashion: The Goths were Christians of a sect known as Arianism (versus the “Catholics” of the official church), and Alaric had given strict orders that his men should respect Rome’s holy churches and monasteries, where many terrified citizens found safety. Stories were later told of devout Christian women who were able to carry religious treasures to safety. But other Romans were tortured to reveal their hidden wealth. The Goths stripped statues and palaces of their precious metals and gems, including a four-foot-tall golden menorah once looted from the Temple of Herod in Jerusalem.

Fighting erupted in many parts of the city, and it descended into savagery when Hun mercenaries ran riot. Fires spread; corpses carpeted the splendid avenues. To the horror of Roman aristocrats, all distinctions of birth were forgotten in the chaos; the monk Pelagius wrote: “Everyone was thrown together and shaken with fear; every household had its grief, and an all-pervading terror gripped us. Slave and noble were one. The same specter of death stalked us all.” After three days, the Goths abandoned Rome, where there was no food for the vast army. But refugees from the disaster would spread across the Mediterranean telling tales of horror, traumatizing, for example, the devout bishop St. Augustine in Roman North Africa. Nearly shattered by the news, he began writing his masterwork City of God to explain why such a tragedy could be part of a divine plan.

In Ravenna, meanwhile, the emperor was unfazed. When a courtier rushed in with news that Rome had “perished” (writes ancient chronicler Procopius), Honorius thought that one of his beloved pet roosters named Rome had died, wailing, “And yet it has just eaten from my hands!” The emperor was indifferent to the city’s dire fate. But he was relieved his chicken had survived.

Along a road lined with thousands of pagan graves and the multilayered catacombs of the Christians, the Gothic army traveled after the three-day sack, leading wagons bulging with loot and a contingent of highborn Roman hostages, of whom by far the most valuable was the 20-year-old Placidia.

Theodosius The Great — Some blamed Placidia’s father, Theodosius, for Rome’s fall. The devout Christian outlawed other faiths, supposedly angering pagan gods. Pictorial Press ltd / Alamy Stock Photo

Alaric assigned his captive to his brother-in-law, a cavalry leader named Athaulf, who was (the later Roman historian Jordanes writes) “a man of imposing beauty and great spirit.” Athaulf ensured that Placidia “enjoyed all the honor and ceremony due to her imperial rank,” traveling in a padded carriage with at least one slave, and perhaps a small collection of silks and jewels. Placidia would turn the disgrace into an extraordinary advantage.

For the next four years, she accompanied the marauding Visigoths around the Mediterranean in what turned into an endless search for grain. As her wagon creaked along the superbly engineered highways, Placidia may at first have tried to maintain her own world of Roman comforts. And yet, historians surmise Placidia would also have been exposed to, and perhaps adapted to, her captors’ way of life. She would have eaten strange Germanic stews around evening fires. To endure the winters outdoors, she probably wore exotic furs and leathers. She may have even tried using soap instead of olive oil while bathing.

She evidently discovered that the “barbarians” were far more urbane than the dismissive Romans realized—or the common image passed down to us today. Their warrior-nobles wore trousers rather than togas, but many leaders had been educated in Rome, spoke Latin and Greek fluently, and deeply admired classical art and letters. Alaric himself had trained in Italy to become a mercenary general and had fought alongside Placidia’s father, Theodosius, at the Battle of Frigidus in 394. The xenophobic Romans refused to accept the Goths as equals or deal with them honestly. But during her captivity, Placidia developed a more sympathetic view, and she decided that an alliance between Roman and “barbarian” was the best hope to keep the empire intact.

Alaric’s superstitious dread must have seemed justified when he became sick and died, probably from malaria, only months after ravaging Rome. The Visigoths were then campaigning in the far south of Italy, and they buried their beloved king at the peninsula’s toe, hiding his tomb so well that its lavish treasures still have not been found today. Chosen as his successor was Placidia’s guardian, Athaulf.

In January of 414, the captive princess astonished Romans by agreeing to marry this handsome new Visigoth king, apparently quite willingly. “Though not tall of stature,” Jordanes writes, Athaulf “was distinguished for beauty of face and form.” For his part, Athaulf was attracted to Placidia’s “nobility, beauty and chaste purity.” The army was by then crossing southern Gaul, modern France, and a lavish wedding ceremony was held in a villa in Narbonne, a lovely coastal city in today’s south of France. A mixed marriage if ever there was one, the rite was Roman in style but attended by local Roman nobles and Goths alike. Sending a clear message through fashion, Placidia wore imperial silks and Athaulf the armor of a Roman general. Together, the cross-cultural pair advocated a radical dream. As Athaulf explained in his wedding speech, his desire had once been to destroy the empire and turn it into “Gothia” instead of “Romania” with himself as a new Caesar. But now he longed for peace. He and his people were tired of their endless wanderings around southern Europe. Instead of fighting for their own kingdom, the Goths would now become Roman citizens, accept imperial laws, become integrated into Rome’s society and defend its borders. In short, Athaulf and Placidia would renew the ailing empire: The royal house of Theodosius could now be backed by the manpower of the Goths.

Athaulf admitted that he had come to this conclusion aided by “the persuasion and advice of his wife, a woman of surpassing intellect and of faith beyond reproach.” It’s very plausible. As the Roman historian Tacitus once noted in surprise, German men, unlike the deeply sexist Romans, valued women’s opinions; they did “not despise [women’s] counsels or make light of their answers.” According to Joyce E. Salisbury, author of the Placidia biography Rome’s Christian Empress, the princess may have privately calculated that this was the only way for her to secure independence: Even if she were ransomed and returned to her doltish brother Honorius, who had no heirs, she would be married off as a pawn in the court’s power game.

As a wedding gift, Athaulf gave his bride 50 young men dressed in silk as her personal guards, each carrying two plates, one piled with gold, the other with precious gems—all plundered from Rome. As marriage hymns were sung, the guests enjoyed a feast featuring Gaulish wines and desserts flavored with rosemary flower honey. It may have been Placidia’s idea that the Visigoths locate their new base in the fertile provinces of Spain, her family’s ancestral homeland. Arriving in Barcino, modern Barcelona, Placidia bore Athaulf a son. Instead of a royal Gothic name, they christened the boy Theodosius after his Roman grandfather, the revered warrior-emperor. The future looked bright.

However, after only a few months, the infant Theodosius died. The mourning Placidia and Athaulf wrapped the body in a gold cloth and laid it in a tiny silver coffin, which after a torchlit procession was buried in a chapel. Worse was to come. In 415, Athaulf was attacked by a resentful servant and stabbed in the groin; the wound soon proved to be lethal. The new Gothic king Sigeric, who seized the throne after Athaulf’s assassination, wanted to remove all threat to his rule and personally butchered Athaulf’s daughters from his first marriage, tearing them from the arms of a bishop who tried to protect them. Placidia was only saved by her royal Roman blood. Instead of being executed, she was forced to walk in front of Sigeric’s horse with other Roman prisoners during Athaulf’s 12-mile funeral procession as an act of humiliation. She was then ransomed for a vast quantity of Roman grain, 600,000 measures, and bundled off to Honorius.

We can only imagine the culture shock Placidia felt leaving the Visigoth band for the imperial capital by the Adriatic, with its dysfunctional court life suffused with decadent luxury, venomous intrigues and stifling protocol. Even as a teen, relations with her indolent sibling Honorius had often been contentious. Now, as Placidia had feared, the emperor insisted that she marry his new top general, Constantius—who in stark contrast to the handsome, young Athaulf was an aging, clumsy and shifty war veteran. Some features seemingly attributed to him are “bulging eyes;” a long, ungainly neck; and a “broad” head. Constantius preferred a soldier’s life to the court, where he often looked “depressed and sullen,” although he was said to be amusing at feasts when drunk. Despite her resistance, the arranged marriage went ahead, a serious comedown for the former Gothic queen.

Once again, Placidia turned the situation to her advantage. Despite his oafish manners, her husband held firm control of the legions and enjoyed a string of victories on the battlefield. Constantius’ status was such that in 421, Honorius even promoted the general to rule alongside him, with Placidia given the title Augusta, the highest rank in the empire. Most important, she had two healthy children with Constantius, a daughter, Honoria, and a son, Valentinian. Honorius was still childless, which made her infant boy the undisputed heir to the Western throne.

A mosaic decorates a floor in the Baths of Diocletian. Peter Barritt / Alamy Stock Photo

Perhaps because she knew that life was so precarious, Placidia threw herself into religion. In 417, she commissioned a cross-shaped church in Ravenna for royal use, Santa Croce, which became one of the artistic wonders of the empire. Its vast dome was designed by master architects from the East using innovative engineering; its marble floors featured circles of rare purple porphyry from Egypt, and the walls and ceilings glowed with colored marble and stucco, and an image of Christ hovering above the four rivers of paradise. But its most ravishing element was a chapel with ceiling mosaics depicting golden stars in the heavens surrounded by celestial religious visions.

“It’s like a jewel box,” Claudia Frassineti, a guide to the treasures of Ravenna, whispered in excitement as we approached, then warned: “It’s quite unimpressive from the outside. You don’t expect it to be so beautiful.” The chapel’s exterior is indeed oddly plain. But those who step beneath its low doorway stop in their tracks with gasps of wonder at the ceiling: 567 golden stars cascade down the cobalt-blue night sky, a gorgeous firmament intended to evoke the gateway to heaven above. It’s a vision with a power that would not be matched until Vincent van Gogh’s Starry Night. In the near-sepulchral darkness, one can make out an array of biblical images—Christ the Good Shepherd and his bearded apostles gazing down benignly; a martyr going to his death on a bonfire; surreal images of the apocalypse, drawn from the Book of Revelation. “Roman mosaics are very dynamic,” Frassineti whispered. “You can see the shadows cast by the flames, the movement of the eight apostles.”

To create the masterpiece, Placidia spared no expense. To achieve the magical effect of the glittering stars, the unknown artists sandwiched a layer of gold leaf between two squares of glass for each mosaic, making every one a different size so they appear to shimmer as a viewer moves below. Despite her apparent ascendancy, Placidia was keenly aware that family politics within the court of Ravenna were unpredictable, and her position precarious. When her lovely chapel was completed, she reportedly spent whole nights prostrated on the floor beneath the candlelit mosaics, praying fervently and often in tears.

Placidia’s anxiety turned out to be well founded. Only months after her elevation as Augusta in 421, her fortunes plunged yet again when Constantius died from a bout of pleurisy. Palace intrigues flourished in the power vacuum that followed, with bizarre rumors spreading that Placidia had become romantically involved with her half-brother. (One chronicler reported: “The absence of restraint in their love for one another and their constant kissing on the mouth caused many people to entertain infamous suspicions about them.”) Relations with Honorius suddenly went awry in 423 when he became convinced that she was dealing behind his back with the Visigoths, and he banished Placidia from Ravenna. She fled to the port with her two young children and hired a ship to travel back to her childhood home, Constantinople. It was a terrifying journey. The vessel nearly sank in an Aegean storm, and Placidia believed her family was only saved by a prayer promising to build St. John the Evangelist a new church.

Incredibly, Placidia’s adventures only became more dramatic. Not long after her white-knuckle escape from Ravenna, Honorius collapsed from edema and died at age 38, leaving the throne to be seized by an upstart palace official named Joannes, who was both capable and moderate, but had no royal blood. Placidia had been cultivating the friendship of powerful female relatives in Constantinople. To ensure their family’s dynasty continued, they helped convince the Eastern Emperor Theodosius II, Placidia’s nephew, to dispatch an army to Italy, depose the usurper and restore Placidia’s 6-year-old son, Valentinian, to his rightful position as emperor of the West. In a stunning reversal of fortunes, Placidia and her two children marched with the legions to victory in 425, then reoccupied the imperial palace in Ravenna. Placidia regained her title “Augusta” and took control of the Western Empire as her son’s all-powerful regent.

The captured Joannes suffered the fate of traitors: His right hand was cut off. He was paraded on a donkey, then beheaded before jeering crowds in the chariot stadium.

For the next decade, Placidia led the Western Empire personally, playing generals off one another, keeping the deadly intrigues of the court in check and building alliances to stave off the new threat from the East, Attila the Hun. Even after Valentinian came of age, in 437, Placidia, now 47, remained the power behind the throne. She legislated on the minutia of daily life, and (according to historian Hagith Sivan) planned a legal reform to streamline centuries’ worth of confusing Roman laws into a single written set, which became a cornerstone of the great project in the Eastern Empire known as the Theodosian Code, the basis of future Roman law in Europe. She took an active hand in church affairs, becoming close friends with bishops around the Mediterranean world, weighing in on urgent theological debates, intervening in a dispute about the succession of the pope and promoting worship of the Virgin Mary. (Less appealingly, she continued her father’s intolerant policy of stamping out non-Christian faiths.) She also remained a devout patron of the arts, expanding her building program to edify the faithful.

Pope Leo I, or Leo the Great, was a friend to Placidia and helped defend Rome by persuading Attila the Hun to retreat and abandon his plans for invasion. Romy Blümel

In Ravenna, her new churches included St. John the Evangelist, built to fulfill her promise to the saint for helping her to survive the Aegean storm. Today, although largely rebuilt after damage in World War II, the church still has a carving of Placidia over its gate.

Her impact was just as powerful in Rome, which she hoped to convert from a secret stronghold of paganism to a beacon of Christianity. She visited regularly, busying herself with pious deeds, forging a friendship with the charismatic Pope Leo I and beautifying churches. One of her finest commissioned mosaics still graces the walls of the Basilica of St. Paul Outside the Walls.

Placidia’s son Valentinian III was an even less successful emperor than her brother, Honorius. Valentinian was assassinated just five years after her death. Chronicle / Alamy Stock Photo

But Placidia had less luck preparing her own family for the responsibilities of ruling, which would one day have catastrophic consequences. Although she made efforts to educate her son Valentinian, he grew up like his uncle Honorius, distracted, vain and indecisive. “Valentinian was a disaster,” sums up Novara of the National Museum of Ravenna. “He was weak.” He dithered in 440, for example, when North Africa was invaded by another brutal Germanic group, the Vandals. The province was lost, cutting off Rome’s main supply of grain, although the emperor scrambled to find replacements from the east.

Later, Placidia’s daughter, Honoria, became the center of a bizarre Roman sex scandal. Historians do not know why Placidia failed to arrange an acceptable early marriage for Honoria, who proved to be as headstrong a character as her mother. After an illicit affair with one of her palace stewards, she was forcibly engaged to a wealthy senator. In protest, Honoria secretly sent a ring and letter offering her hand in marriage to Attila the Hun—an astonishing act that set Attila, who was referred to as the Scourge of God, on a path to Italy. Psychologists can only speculate: Was Honoria trying to emulate her mother by uniting imperial blood with “barbarian”? Her proposal, when it was discovered, was regarded by Romans as treason. The Huns, who rode tough warhorses, firing arrows with deadly accuracy, were regarded as the stuff of nightmares. They devoured raw meat, and their ritual facial scars and stocky bodies made them (one Roman author noted) “so prodigiously ugly and bent that they might be two-legged animals.” Honoria avoided execution—Placidia argued for her daughter’s life—but was banished in disgrace.

Placidia died quietly in her sleep in Rome in 450 at age 60, presumably secure in the belief that her dynasty was strong and the Christian God would safeguard the empire. She was buried in the Theodosian family sepulcher at St. Peter’s church on the Vatican Hill in Rome.

She could hardly have imagined that within five years, her son Valentinian would be slashed to pieces while practicing military exercises on Rome’s Campus Martius by two men loyal to a general whom he had murdered. Nor did she live to see her daughter’s offer of marriage to Attila come back to haunt the empire in 452, when the Hunnish king and his cavalry stormed into Italy, demanding that Honoria be handed over and the wedding proceed. Placidia’s old friend Pope Leo personally confronted Attila in the north of Italy and threatened him with divine punishment if he did not turn away. In what was hailed as a miracle, Attila did leave. But according to the chronicler Priscus, Attila’s inner circle had urged him to back down, reminding him that Alaric had died shortly after sacking Rome in 410.

Leo did not repeat his success when the Vandal armies arrived a few years later. After they pillaged the city in 455, the Western Empire spiraled rapidly toward disaster, then crumbled entirely. The traditional date for the collapse is 476, when a Germanic leader named Odoacer took Ravenna and proclaimed himself king of Italy.

A ceiling mosaic in the Mausoleum of Galla Placidia in Ravenna depicts the entryway to heaven. Getty Images

Pope Leo I presided over the funeral for Placidia’s first child, Theodosius, who was the son from her first marriage to Athaulf and died while still an infant. Chronicle / Alamy Stock Photo

The so-called Dark Ages had begun, although historians now argue that the continuities with the classical age run deeper than the ruptures. As two historians put it bluntly in a recent revisionist history, The Bright Ages: “Rome did not fall.” These “Dark Ages” glowed with erudition and art, creating new starts for civilization that would shape the modern world. The Roman Empire flourished in the East for another 1,000 years, with opulent Constantinople, founded as the “New Rome,” anchoring the region of Byzantium. Placidia’s vision of a peaceful union between Romans and Goths did not endure. But her idea of Christendom as a coherent cultural unit, with Rome as its sacred center, would become a defining feature of Western Europe for centuries.

“Placidia was an impressive and significant ruler,” Salisbury concludes in her book. “She had intelligence, an indomitable will and political instincts that let her navigate swift changes in fortune throughout her life. She managed to thrive during the turbulent twilight of the Roman Empire when many prominent people did not survive.” Placidia also “influenced both battles and theology,” she adds, and cleverly manipulated male generals and bishops to keep herself in power. Most important for posterity, she “recognized the importance of art and architecture in shaping public opinion.”

Attila the Hun was eager to become Placidia’s son-in-law after receiving what he interpreted as a proposal from Placidia’s daughter. Commons.Wikimedia.org

Indeed, The Bright Ages starts with Placidia’s most enduring legacy, the mosaic-covered mausoleum, as a bridge between the ancient, medieval and modern worlds. The chapel’s ceiling of glittering stars in a blue heaven has influenced artists for centuries, including the author of one of the West’s greatest works of literature.

“Dante Alighieri lived in Ravenna for five years while writing The Divine Comedy,” said Frassineti when we visited. “He certainly came to the mausoleum for inspiration.” The painter Gustav Klimt was “deeply affected” by the city’s gold-saturated mosaics during a visit in 1903. (“He adored the details.”) But perhaps the most surprising artistic influence was on the American composer Cole Porter, who purportedly wrote “Night and Day” after gazing in rapture at the mausoleum’s starry ceiling.

Mausoleum of Galla Placidia — The fifth-century structure—which does not contain Placidia’s remains—is now a UNESCO World Heritage site. Smartshots international / Getty Images

In her twilight years, Placidia ordered the tiny silver coffin of her infant son Theodosius—the child she had borne at age 24 with Athaulf—to be exhumed in Barcelona and shipped to Rome. She arranged for the baby’s coffin to be interred alongside her own in St. Peter’s, so the two could rest in peace together until the Christian vision of the resurrection would reunite them in heaven. She left no record of her motives, but it seems a moving testament to one of history’s most unlikely love affairs, between an open-minded “barbarian” king and a strong-willed Roman princess.

Tony Perrottet | READ MORE

Tony Perrottet is a contributing writer for Smithsonian magazine, a regular contributor to the New York Times and WSJ Magazine, and the author of six books including ¡Cuba Libre!: Che, Fidel and the Improbable Revolution that Changed World History,The Naked Olympics: The True Story of the Ancient Games and Napoleon's Privates: 2500 Years of History Unzipped. Follow him on Instagram @TonyPerrottet.