The plague is still raging in the city of Rome, and Pope Gregory leads a procession through the city chanting chants... At this moment, he saw an angel standing on the castle of the Kresinzi family, wiping the blood from the sword, and then sheathing the sword. The Pope knew that this heralded the end of the plague, and it was. Since then, the castle has been known as Castel Sant'Angelo.
—Aurea Legenda, 46
Memories of the Justinian Plague and the "End of the World"
The Golden Legend, a popular collection of biographies of the saints in the Middle Ages, chronicles the catastrophe brought to Rome by the plague of Justinian in the 6th century AD and the coming of angels to end the plague. Countless tourist brochures or websites that introduce Castel Sant'Angelo will refer to this passage of castel Sant'Angelo's "origin myth" to a greater or lesser extent.
Castel Sant'Angelo is one of the most popular attractions in the city of Rome today. The quaint and heavy castle was converted from the mausoleum of Emperor Hadrian, standing on the tranquil edge of the Tiber River, and together with the elegant and dignified statues on the Holy Angel Bridge in front of the entrance, it constitutes a beautiful picture. Countless famous scenes from history, drama, movies and novels take place here. Overlooking all this is the bronze statue of the archangel Michael at the top of the castle, the work of the 18th-century Flemish sculptor Peter Föshafeldt, which vividly embodies the gesture of the archangel sheathing his sword in The Golden Legend. Although the statue is not very old, it is a reminder that the trauma left in the city's memory by the Plague of Justinian in the 6th century has not been completely forgotten even if it has been more than a thousand years old.

Castel Sant'Angelo
The story in Golden Legend is just a snapshot of the affected cities across the Mediterranean during the plague of Justinian. The plague lasted for nearly two centuries, so named because it broke out during the reign of Emperor Justinian, and many scholars regard it as the largest disaster in the Mediterranean world before the Black Death in the 14th century, and even believe that it had a decisive influence on the course of civilization in the post-Mediterranean world. Due to the fragmentation of existing ancient historical data, the destructiveness of the plague is still incalculable. But through the descriptions of historians such as Prokobi, one can glimpse the bleak scene of the great cities of the eastern Mediterranean at that time, such as Constantinople, Antiochus, and Alexandria. And their records have long received full attention from experts and scholars at home and abroad.
The War of Conquest by Emperor Justinian and the trade exchange of the Mediterranean world caused the plague to invade the major cities of the western Mediterranean from east to west along important land and sea routes. The western part of the Mediterranean under the plague presented a different picture in the historical documents of the time. Unlike Eastern historians like Prokobi, who inherited the classical Greek tradition of historiography and used a Thucydean rational approach, the Latin historians of the western Mediterranean showed more religious feelings, and their descriptions were full of biblical metaphors, presenting us with an "end-time" picture.
The 8th-century Italian historian Deacon Paul documented in detail the spread of the plague in northern Italy: at first, indelible marks appeared on the walls, on the doors, on the utensils, and on the clothes of the people. Then the plague began to break out. At first, lumps appear on the patient's body, followed by an unbearable high fever, and many people die on the third day after the onset of the disease. Frightened people fled. Some have left behind the bodies of their parents, which have not yet been buried, while others have abandoned their children with high fevers. Some people have difficulty giving up their family and staying behind to hold funerals for their families, but often halfway through the funeral, they fall down on their own. Paul said that the plague left a dead silence everywhere, but there were also many who heard the faint sound of trumpets echoing in the distance, and they looked around, and there was no sign of the army passing by, only the corpses of people.
The plague struck the city of Rome around 590, and Gregory, bishop of Tours, tells us in his History of the Franks that a Frankish priest who was in Rome at the time experienced the disaster. Not long before, Rome had just experienced a major flood. Two consecutive natural disasters have put people in the shoes of the end of the world. Someone saw many poisonous snakes and a huge dragon appear on the bed of the Tiber, some saw countless rain of arrows falling from the sky, and some saw a golden list with the names of people who were about to die in the plague. In the minds of most people at that time, the plague was brought by the devil, and the evil dragon was the embodiment of the devil. After Pope Pelagia II fell ill and died, the newly enthroned Pope Gregory told everyone that god's sword of wrath was punishing the sins of mankind, and he called on people to organize a procession and chant chants to eliminate disaster.
So far, in all the historical accounts of the plague, there is no information about the archangel Michael, but these apocalyptic descriptions have provided sufficient fodder for the story of the angel's coming. So how did the angels enter this scene of "end-time memory" and be "summoned" by the people of the hereafter to quell the plague? This is related to the popularity of the cult of the archangel Michael during the Plague of Justinian.
There is a battle in heaven. Michael fought with his messengers against the dragons. The dragon also went to war with his messengers. There is no victory[ for the dragons, and there is no place for them in heaven. The great dragon is the ancient serpent, called the devil, also called Satan, who deceives the whole world. He was thrown to the ground, and so were His messengers.
Revelation 12:7-9
The multi-faceted angel on the castle
In the biblical canon, Archangel Michael is a low-key character. In the few appearances, he is described as the leader of the angels, holding the status of "archangel", and his main duty is military, that is, to lead the angels in battle against the devil. Since ancient times, works of art about Michael have tended to see him as an evil punisher, showing him dressed in a robe, holding a sword, and stepping on a demon or a dragon. In the early Middle Ages, legends about Michael gave him the image of the "healer".
The multiple images of the archangel Michael in the medieval period are epitomized in a work called De Apparitione Sancti Michaelis. It is one of the earliest documents in the western Mediterranean to record the legend of the archangel, completed around the 8th century AD, including the legend of the three appearances of the archangel at Mount Gargano. His first appearance was when a shepherd tried to shoot an unruly bull with a poison-coated arrow. The archangel protected the bull, he turned the direction of the poisoned arrow, shot the shepherd, and then he appeared to the crowd and told the people that he was always watching over all things on earth. The second legend tells that shortly after, in a war between the natives and the pagans, the archangel reappeared and punished the pagans with his mighty powers. The locals were so terrified of the power of the archangel that the archangel appeared for the third time and instructed the local bishop to build a chapel dedicated to him in a cave. It was discovered that the spring water in the cave had miraculous powers, curing many patients with high fevers during the plague. The Cave of St. Michael on Mount Gargano has since become a famous pilgrimage center in Western Christendom.
Archangel Michael
The legend of the archangel's appearance was first circulated during the period when it was ruled by the Lombards. Deacon Paul mentions several times in his History of the Lombards that this angel with multiple functions as a military leader, punisher, and healer was quite popular among the belligerent Lombards. A similar story soon appeared in the Frankish kingdom, where legend has it that the archangel Michael appeared three times to guide people to build a church on a cliff, and when the church was built, many miracles of the recovery of the sick took place, and since then it has been known as Mont Saint Michel after him.
In fact, it was during the same period that historical records of the city of Rome mentioned that Emperor Hadrian's mausoleum had been dedicated to the archangel chapel. The mausoleum had also been converted into a fortress to hold the city of Rome, and given its military function, the angel first "descended" on the site, more likely out of the worship of his power as archangel and punisher, hoping that the punishing angel full of divine power would help the Romans drive away the invading foreign enemies. However, with the passage of time, this origin has gradually been forgotten. Later generations have reshaped the castle's "origin myth" through hazy memories intertwined through the various eras. Eventually, fear of the plague and hope for a cure for disease replaced the worship of power, and now people prefer to believe that once stood on the castle was a guardian angel who sheathed his sword and declared the end of the disaster.