These days, most people hearing the name “John Snow” will think of the character Jon Snow from HBO’s Game of Thrones, a hugely successful series based on the books by George R. R. Martin. Many of the 6 million+ viewers of this fantasy series may not know that there was another John Snow, perhaps one without the coal-black curls and swarthy good looks, but a man who changed the world of medicine and saved millions of lives. What does a fictional hero who wields a magical sword to destroy the undead atop a 700-foot wall of ice have to do with a Victorian-era physician who wielded nothing heavier than a fountain pen as he collected thousands of data points in a 1-square-mile neighborhood of London? The answer may surprise you!

Today, John Snow is recognized as the father of epidemiology, the study of infectious disease outbreaks. During his lifetime, however, he was known as a respected anesthesiologist who proposed some outlandish ideas about the spread of disease. His early work proposing a connection between store-bought bread (with added aluminum) and rickets, a pervasive childhood leg deformity, was ignored. (Science would prove him correct 60 years later.) His idea that deadly cholera outbreaks were microbial in origin and transmitted via the fecal-oral route (ingestion of water contaminated with feces from an infected person) were rejected and criticized. Despite these setbacks. John Snow continued being a rebel, pursuing the data to back up his theories and presenting the data visually in one of the world’s first infographics.

Meanwhile, the fictional Jon Snow faces similar struggles (albeit having perhaps less of an impact on the world’s health, but that could be debated). As we will see, his fictional struggles serve as an analogy to John Snow’s, and in some ways, to the experiences of any scientist on the cutting edge of discovery. [WARNING: There are some spoilers!]

They are both older children in large families. John Snow, the father of epidemiology, was the oldest son of a poor family of nine living in York, UK, where his neighborhood was threatened by frequent floods. Jon Snow wasn’t poor - he was an older (albeit illegitimate) child of the ruling family of Winterfell - but his upbringing had its challenges. Being an older brother can bring out the best in a young man destined for greatness! They both grew up quickly, starting their adult lives at a young age. At the age of 14, John Snow, the son of a poor laborer, travelled hundreds of miles to become apprenticed to a surgeon. After only a few years of apprenticeship, he managed to be admitted to medical school and become a physician in his own right in only a few years, an incredible feat for a young man from a poor family with no formal education past the age of 14. Also 14, Jon Snow, bastard son of the Lord of a bleak and bitterly cold kingdom, decides to join the Night’s Watch at the Wall, a military outpost hundreds of miles from his home. Like epic heroes, their destinies begin with a voyage from the known into the mysteries of the unknown. They both left their stable lives to pursue their destinies “in the field.” John Snow, a physician committed to solving the enigma of cholera, abandoned the safety and security of the laboratory and clinic to conduct research in the poorest areas of London. There he sought out and interviewed inhabitants of the Soho neighborhoods being ravaged by a cholera outbreak that would kill over 1:10 of the residents in just a week. Jon Snow, a well-respected member of the Night’s Watch, left the safety of the military outpost to venture into dangerous territory, living amongst the “wildling” inhabitants in an effort to learn more about recent events he believes are a threat to the entire country. To help the people, you must live with the people (and to defeat your enemy, you must know him). They both had ideas that were considered crazy, if not dangerous. John Snow, working in a medical field that had yet to discover the germ theory of disease, was skeptical of the accepted theory that disease was spread by polluted air from swamps or graveyards. He began to doubt this theory when he treated patients with cholera far from swamps or graveyards: coal miners working deep underground. His studies led him to believe that cholera had a microbial source, most likely stemming from drinking water contaminated with fecal matter. His ideas were rejected by his peers, considered distasteful and even inflammatory. Even after he had demonstrated his theories through field work, resulting in the closing of one contaminated well, local government officials denied the connection to sewage contamination and reopened the well. It took decades for the establishment to accept his theory fact. Jon Snow also had theories that were questioned and rejected. One of those theories was that the White Walkers, mysterious killers from beyond the realm that most had relegated to myth, were in fact real and coming to destroy the kingdom were ignored and rejected, even in the face of undeniable evidence. It seems that even in the face of facts, the ruling administrators will still fight change.

Both men chose a life of strict abstinence and self-denial. At the young age of 17, John Snow became a vegetarian and took up the “temperance cause,” a movement espousing complete abstinence from alcohol and a strict moral code. He followed these tenets until his death, lived plainly, and remained unmarried. Jon Snow’s decision to join the Night’s Watch also required that he live under a strict code of conduct, separated from family and friends, never marrying, and a lifetime of self-denial of most of life’s comforts. Who has time for worldly temptations when there are greater challenges ahead?

Both died at a young age. John Snow’s life of discovery and invention ended at his desk, writing a treatise on anesthetics. Pen in hand, Snow suffered a severe stroke and died quickly at the age of 45, to be mourned by his close friends in a simple ceremony. Jon Snow (at least as far as we know) also died a young man. While his death was markedly different, Jon Snow, too, was mourned only by a small number of close friends. While we still do not know the outcome of Jon Snow’s death, the now-revered physician Snow would be lauded and celebrated a century later for his pioneering work in field he created, epidemiology. Death is ultimately the great equalizers (unless you become undead, in which case… well, we shall see).

Both were talented fighters in their field of choice. John Snow may have never held a sword in his hand, but he did his part in defending his nation. Not only did he conduct research that led to safe dosages of anesthetic, he became the leading anesthesiologist of his time, administering obstetric anesthetic to Queen Victoria herself during the birth of her two youngest children. His indefatigable work in proving his theory of a microbial origin of cholera in contaminated water, he helped protect the United Kingdom from the cholera pandemics that swept the globe. Fighting a different enemy, Jon Snow excelled both with a sword and as a leader. He quickly rose through the ranks of the Night’s Watch, keeping his colleagues safe while never abandoning his pursuit of the mysterious White Walkers. Focus and determination, alongside a heavy dose of talent, is an excellent combination for greatness.

They both were trying to vanquish a mysterious, powerful, lethal enemy. John Snow first encountered cholera when he was sent alone, as an 18-year-old apprentice, to treat coal miners being ravaged by the disease. It was 1831, and the disease that had originated in India millennia before had finally reached the northern UK thanks to newly-invented steamboats. No one knew much about the disease that caused sudden, terrible diarrhea, vomiting, and for 10% of cases, death. John Snow’s early experience led him to study cholera, working to prove a microbial origin. At the time, the prevailing beliefs about disease still focused on the miasma theory of “polluted air,” so his theory was rejected wholesale. In a way, cholera was not his only enemy – he also had to fight against the resistance to change in the scientific community. The bacteria that causes cholera, Vibrio cholerea, was finally isolated in 1854, but the idea that water contaminated with human waste carried the organism was not accepted for decades. When it was, cities upgraded sewage systems, keeping cholera pandemics from their shores. Fictional Jon Snow’s enemy serves as an excellent analogy for this struggle. This young newcomer proposes a mythical source for the deaths taking place over the Wall. He himself has seen a White Walker, but has no fellow witnesses to vouch for him. He tries to convince his colleagues in vain, even as these “wights” continue to come closer and closer to the kingdom he has sworn to protect. In the end, Jon Snow’s fellow Watchmen might wait to face the truth until the enemy is right at their door (we will have to wait and see how that turns out), in the same way that John Snow’s opponents had to face the awful truth (sewage-contaminated water) even as new outbreaks were claiming lives all around them. Ultimately, denial is a fierce opponent.

Just as Jon Snow had to continue to defend his ideas in the face of opposition, betrayal and death, so do many of history’s innovative scientists. John Snow is not alone in being ignored or rejected for his scientific ideas. Ignaz Semmelweis was laughed out of the room for proposing that doctors transmit disease by not washing their hands. Alfred Wegener’s ideas of continental drift were not accepted until 30 years after his death. Many scientists were ignored (and even punished) for proposing a heliocentric model of the solar system. Innovators are, by nature, rebels and fighters, even if they wield pens instead of swords. Think of these scientists if you begin to doubt that John Snow isn’t a heroic equal to the swashbuckling Jon Snow!