Gaius Marius Jonianus (580-636): The Great Tang Roman

Few parts of the globe have failed to bear witness to Roman military might, and a recent discovery has made that list of places even shorter. A humble Buddhist shrine was discovered at a remote battle sight in Northern China. The tomb inscription reads “The Great Tang Roman”. A thorough search of both Roman and Byzantine archives identifies The Great Tang Roman as Gaius Marius Jonianus (580AD – 636AD). Gaius was born in 580 AD to a family of merchants and traders in Thrace, northwest of modern day Greece. While he assisted the family business by handling the transportation aspect of the enterprise, he often dreamed of bigger things. As the second of three sons, however, he would not receive an inheritance. An entry found in his personal journal reads:

My formative years working for my father’s trading company certainly taught me a great deal and I genuinely enjoyed the work. I was eight years old when I starting traveling in the caravan and I was fourteen years old when I managed my first trip, but as the second son I would always be working for my older brother. He did offer to make me a coinheritor; however, I refused since in the eyes of the public I would simply be the second in command, which was unacceptable. I wanted to forge my own legacy.”

Leading the caravans provided Jonianus with many skills that would prove invaluable later in life, including horseback riding, self-defense, long and short term planning, logistics and supply, coordinating large groups of people and animals, and navigation.

Jonianus’ chance to forge his own path came in 600 when a massive group of Avars, a nomadic people from the steppes, swept into Thrace and made any activity outside of the fortified coastal city meant certain death. Another journal entry describes how he returned to his family home after a trade mission to find the house aflame and his family riddled with arrows. In response to this gruesome sight Jonianus allegedly killed those Avars who stuck around after attacking his home. While his infamous temper is confirmed in reliable sources, historians believe that this story is largely exaggerated. It is unlikely that he would have been able to have fought off a horde of mounted archers without armor. It is possible, however, that he did exact his vengeance on any isolated Avars he encountered on his retreat to Constantinople.

Since a merchant career became impossible after the Avar conquest, Jonianus enlisted as a cavalryman and quickly rose through the ranks. Reliable sources with information on his career from 600-617 have not been found and were probably destroyed in the chaotic years following the initial Sassanid (Persian) invasion in 602. In early 618, however, Jonianus was personally tasked by the emperor Heraclius to scout every hectare of land in Armenia, where the emperor planned to lead a counter-attack once a new army could be raised to replace the now gutted Roman military. When Jonianus received his assignment, the Sassanids had already captured most of the Middle East, with the exception of Anatolia (modern day Turkey). While he was scouting, the Sassanids captured Egypt, the bread basket of the empire, which made his mission more critical. If the Emperor’s counter attack in Armenia failed, the empire would certainly fall.

Unfortunately, the only known records of the mission come from Jonianus and his subordinate officers, which were almost certainly written after the fact since the mission took place behind enemy lines and any documented evidence of their mission would have been catastrophic. Based on the success of Heraclius’ campaign in Armenia in 624, military historians surmise that Jonianus’ mission yielded bountiful results. This campaign is also where evidence of his infamous temper started to emerge. In the words of Septimius Lombardicus (Septimius the Lombard 592AD – 650AD), his second in command:

“Gaius’ command style was unique because he would craft battle plans that incorporated the creativity of his subordinates. While this method worked most of the time, Gaius was the only commander to employ this concept. Despite the superb training of Roman soldiers and officers, we simply were not used to this amount of latitude. One of the officers, Julius Constantine, took advantage of this latitude and acted completely without Gaius’ orders. This gaff nearly led to being seen by the Sassanids. When Gaius found out about this he was so enraged that he picked the man up by the neck and snapped it with his bare hand. Each of the men took turns carrying the corpse as we transported it to its coffin in the Black Sea.”

Another subordinate officer, Justinian, speaks to Gaius’ effectiveness in battle.

“There is no doubt that our expedition into Armenia succeeded brilliantly due to Gaius’ genius. His experience leading caravans gave him a deep understanding of supply lines, travel times, terrain and enemy language. Since our mission was to scout the enemy we were under orders not to engage the Sassanids unless there was no other option, but Gaius would attack whenever he could anyway because he loved to fight. It certainly helped that he never lost a skirmish. Militarily speaking, he was able to understand the environment as well as the capabilities of our troops and the Sassanid troops better than anyone else. He could also identify the enemy’s moves faster than anyone else; perhaps even before the opposing force. Since we only numbered 100 men all engagements with enemy troops were small, but they were always on Gaius’s terms. The heathen fire worshipers were sent to hell before they were aware of the fighting”.

Jonianus’ thirst for large scale battle would have to wait because after his scouting mission was complete, Heraclius’ army was still not fully trained and not ready for battle. Instead he would be sent on an important mission to China to secure a military alliance, which would trap the Sassanids between two of the three super-powers of the classical era.

The most efficient route to China would be to sail from Anatolia to India by way of Egypt and then march from India to China. This was impossible, however, since the Roman Navy was deployed in the defense of what was left of the Roman Empire. The alternative was to march from Anatolia through Mesopotamia to the coast of present day Kuwait. This option could have been a death sentence since it marched straight through Sassanid territory, which is exactly why Jonianus took this route. He selected eighty of his veteran troops from the Armenia campaign and led them across the desert pretending to be a small group of merchants with bodyguards. Thanks to his experience as a merchant, Jonianus and his troops made it successfully through enemy territory and onto a boat to India.

The “Arcani Novus”, as the troops fancied calling themselves, reached India in the summer of 621. Here they made their first contact with Buddhist monks coming to and from China. Trade routes were vital to the spread of Buddhism into China and, by the time of the Roman arrival, many Chinese had been Buddhists for a significant amount of time[1]. Traveling with Buddhists provided Jonianus with a reliable route to China as well as easy access to food, water and other supplies without the need to raid or steal. Despite their military prowess, the Arcani Novus were only eighty men strong in a place they new nothing about; they were ignorant of the area’s geography, language, culture, customs and history.

These subjects were extremely important to a military leader back then and remain so to this day. In his journal, Jonianus writes about his desire to learn these topics.

“After disembarking from the ship, I impressed upon my men that I knew nothing of this foreign land. While I encouraged them to learn about their new surroundings, I reminded them that they must never fail to do so in a manner befitting a representative of Romania[2]. After the… incident with Julius Constantine, however, I doubt anyone had any misgivings about my meaning so I do not think there is cause to worry. As for my own inquiries, I was fortunate to learn that this land had well-established trade routes with China within hours of disembarkation. Furthermore, these trade routes have a sizable population of clergy belonging to the native religion here. While I do not relish the thought of long trips with men of the cloth, it is the easiest and most reliable way to get to my destination in a timely manner while simultaneously learning all I can. The image of foreigners on a pilgrimage should also help us avoid being seen as hostile despite being heavily armed.”

By the time Jonianus arrived in China in 622, the current ruling dynasty –The Sui – was embroiled in a war against rebellious factions and was in no position to ally with Rome[3]. Using his newfound knowledge, Jonianus and the Arcani Novus set out to scout the military balance of power.

After months of observation from the shadows, Jonianus decided the best faction to side with would be the future Tang dynasty, which would complete its takeover of China in 624, two years after the Romans arrived [4]. The main issue with the first Tang emperor was his Daoist learning’s. Jonianus had learned about China through Buddhist monks. He was also keenly aware of the rivalry between Daoists and Buddhists in the upper echelons[5]. “I fear that anything more than a cursory examination into my background might give the false impression that I favor Buddhists.” Jonianus writes in his journal, “It is my belief that politics have corrupted whatever good the religions of the world have to offer. While my own troops understand that I do not defend or prosecute any religion, they are my brothers and sons from whom I have garnered trust and, in so doing, put in constant risk of death in battle following my command. The Tang, however, do not know or trust me, nor should they at this early stage. I am certain the Tang will be victorious and should they refuse my embassy I might fail to save Romania.” In the following entries, Jonianus details his plan to keep the fact that he has soldiers a secret and only introduce himself while he searches the Tang camp for a Buddhist ally or at the very least someone whom he could gain enough leverage over that should any religious inquisitions arise he could at least soften the blow. The ally he found was the future Taizong Emperor.

The future Taizong Emperor was already vying for power with his brothers and, by all accounts, Jonianus was able to easily befriend the man. While Jonianus infused the main Tang effort with Roman military wisdom, he provided even more wisdom to Taizong in addition to having the Arcani train troops who were loyal to Taizong in secret. Jonianus remarks that “the Chinese do not have the same level of military culture as we Romans. We are able to impart a great deal of practical and theoretical military knowledge to Shimin and his troops which will give him an indisputable edge over his father and brothers”. It is interesting to note that Jonianus uses the emperor’s first name. This has led historians to theorize that the two leaders had a genuine friendship, which was strong enough to circumvent formal titles in an age where honorifics were hugely important. The counter argument is that if their friendship was so strong why is Jonianus’ identity almost entirely absent from the historical record of China? This poses an interesting question since there is not a great deal of known material on the Sino-Roman relationship. The most popular explanation for this is that the Arcani carried out the assassinations of Taizong’s brothers. In an attempt to distance himself from the unfilial acts without alienating the Romans, Taizong simply did not write about their existence instead of placing the blame on their shoulders.

This cover up clearly failed, however, since according to legend, when Taizong ascended to the throne after killing his brothers in 626 he was called before the Chinese lord of the underworld to account for his actions. While his response was sufficient to avoid punishment, he was persuaded to publish Buddhist text as a way to repent[6]. Taizong’s new patronage of Buddhism conflicted with the urge for additional conquest and military action held by the emperor, his generals and especially Jonianus who had spent many years with the goal of trying to secure China’s support against the Sassanids [7]. By the time tentative Chinese military support was obtained, the war with the Sassanids had ended with a Roman victory.

With no pressing military concerns back home, Jonianus remained in China to establish, grow and maintain Sino-Roman trade relations. Ever the fighter, Jonianus often led expeditions against threats to the Tang dynasty. It was during these conflicts that he gained the nickname “The White Death”, seemingly referring to his skin color. The conclusion we can draw about these victories is that they were absolute. In the words of Septimius Lombardicus “The Tang claimed that they believed it would be most effective to keep Jonianus’ victories as vague as possible in order to create a mythos around him. A boogeyman immobilizes its enemies with fear. Personally, I think it’s because they couldn’t stand to see a foreigner win grand victories that the Tang couldn’t achieve themselves. Jonianus, on the other hand, couldn’t have cared what happened afterward as long as got out of the Forbidden City and waged war. I have never seen my good friend happier.” These battles would prove to be his last, however, since in 634, he was summoned home to deal with the Muslim armies that had surged from the Arabian Peninsula to defeat the Romans in every engagement. Jonianus’ departure also weakened the Chinese military under Taizong as his military campaign into Korea towards the end of his reign was highly unsuccessful[8].

After settling his affairs in China, Jonianus and the Arcani started journeying home. Jonianus was fifty four years old and his old age started to show after reaching India. Just prior to boarding a ship home he fell ill and was bedridden for almost a year. Septimius wrote “Jonianus was so sick and should have died in days. Some say his survival was an act of God but I know better. In truth, he was kept alive by the power of his rage at the thought of not getting a chance to defend his home in open battle under the Roman banner.” Though he recovered enough to board a ship home, Gaius Marius Jonianus was killed when pirates raided his ship. According to legend, his final words were “Not even death will stop me from defending Rome. From heaven or hell my spirit will guide our soldiers and generals until there is no more Roman blood left to spill”. When word of Jonianus’ death reached China, Emperor Taizong commemorated the Roman who had given many years to China by building him an honorary tomb where historians first learned of The Great Tang Roman.


[1] Hansen, Valerie. The Open Empire: A History of China to 1800. New York: Norton, 2015. Print. Page 143.

[2] How the Byzantines referred to their territory. In this context, “Romania” roughly translates to land of the Romans. I don’t now if it is related to the modern country of Romania

[3] Hansen, 178.

[4] Wills, John E. Mountain of Fame: Portraits in Chinese History. Princeton, N.J.: Princeton UP, 2012. Kindle. Page 129.

[5] Hansen, 141.

[6] Hansen, 179.

[7] Wills, 131.

[8] Wills, 131.

My name is Jonah Burstein and I am a senior at the U of R majoring in business and minoring in history. On campus, I am a member of the club baseball team. I am working to become an entrepreneur after I graduate.