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Sometimes the drive to discover and record your observations can outlive you.

For more than a thousand years, doctors from Spain to Persia looked to one man to define what it meant to practice medicine: Galen.

Galen of Pergamum was born around 129 A.D. He was Greek but grew up in Anatolia, in modern-day Turkey. Descendants of Plato and Aristotle, the Greeks were renowned in the Ancient World for their skill in science and art.

Galen's father was a wealthy architect. He saw to it that Galen received the finest education in philosophy, literature, and medicine. As a boy, Galen studied the renowned work of the Greek doctor Hippocrates who, already 500 years before, had established medicine as a profession. His famous Hippocratic Oath -- a promise taken by physicians throughout history to uphold specific principles of medical ethics -- remains of paramount significance in the health professions to this day.

When Galen was 19 his father passed away. Galen decided to use his inheritance to follow the advice of his hero, Hippocrates, who believed that a good doctor needs to travel the world to learn medicine. Galen wandered for ten years, learning all he could from local healers and visiting the renowned Hospital of Alexandria.

Galen returned home to become a doctor to gladiators in the city of Pergamum. Treating the wounds of fighters, Galen became revered not only for his inquisitive scientific mind but for his attentiveness to injuries. In under four-years, the death rate among gladiators fell 90%, making Galen famous.


Galen's world was dominated by the Roman Empire, which ruled all of the Mediterranean. As Galen became famous for his skill as a healer, he was recruited to become the doctor to the Emperor in Rome in 162. Galen was vocal in his then radical view that diet and exercise were crucial to health, and that the mind and body functioned together. His ideas annoyed many conservative Roman doctors, who feared they would be dismissed because of Galen's superior knowledge and skill. On one occasion, Galen fled Rome out of fear that he would be poisoned by his rivals, only to return when the Emperor demanded his services to fight the Plague. In the end, Galen outlived his rivals, practicing medicine in Rome for 45 years.

Galen's skill at surgery was legendary. His dutiful and careful dissection of animals aided him in discovering a great deal about the circulatory and respiratory systems of the human body. Galen deduced that cataracts could be cured by surgical removal in a procedure shockingly similar to that which is practiced today. He adapted many of Hippocrates' ideas regarding how sickness is caused, helping to extend the popularity of his childhood hero.

But perhaps most importantly, Galen carefully recorded all of his findings in writing. He wrote 500 treatises in his lifetime, amounting to more than 10 million words, more than any other ancient author. While many of Galen's books do not survive, his vast output ensured that he would never be forgotten.


Galen died in 200 A.D. The Roman Empire in which he lived gradually collapsed over the next 250 years, leaving Galen's writing and knowledge forgotten. For a time. But buried books can be dug up and rediscovered. And that's just what happened.

Beginning in 830 A.D., Muslim writers in the Middle East discovered and translated copies of many of Galen's treatises. Muslim doctors adapted Galen's theories into the basis of Islamic medicine, bringing the ancient Greek doctor back to life throughout the Middle East, Africa and Spain. Not bad for someone who had been dead for almost 1,000 years!

While many of Galen's theories were eventually disproven, his work ethic and drive to discover remain an inspiration for modern doctors, who continue to look to Galen as one of the greatest scientific minds who ever lived. That's why he's a Time Traveler Tours #HistoryHero. Many thanks to Jennifer Cozzone of London, San Francisco, and Marseilles for nominating him.

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