## Alexandria: The Most Important City in History

In 332 BCE, Alexander the Great’s incredible military campaign advanced on Egypt. As his armies moved in, the people there regarded Alexander as a savior, hailing him as the Son of the Most High God, and declaring him Master of the Universe. The young conqueror quickly fell in love with the country, and in the following year, he founded a new capital city: Alexandria-by-Egypt. From its very inception, Alexandria was created to be one of the most important cities in the world. Its ports became a prominent trade destination, in the Mediterranean, and its culture flourished and prospered from a mix of disparate peoples, religions, and philosophies, even at its onset. The Lighthouse of Alexandria was an incredible and beautiful building, standing over 400 feet tall, regarded as one of the Seven Wonders of the Ancient World. But, without a doubt, the most incredible and amazingly important feature of Alexandria was the Museum.

The Museum of Alexandria became, almost immediately, the center of knowledge in the ancient world. It was not a museum, in the modern sense, but rather more like a modern research university. Students went there to learn all they could about the sciences of the day, while the teachers and academics received state salaries to simply do research and increase the knowledge of Mankind. The Museum boasted an incredible library, one which would quickly become the largest collection of books in the Ancient World. A tradition was developed, in the city, whereby foreign visitors would allow any books which they brought with them to be copied, so that the Library’s stocks would continue to increase. Vast amounts of knowledge were developed and stored in Alexandria.

The Museum was destined to make Alexandria-by-Egypt the most important city in the history of the world. An inordinately large amount of our modern knowledge of mathematics and science is owed directly to men educated or employed by this institution. What follows are brief descriptions of just 16 such scholars.

## 1. EUCLID (c. 300 BCE)

I begin with my favorite. We know very little about Euclid‘s life– even the years of his birth and death are completely lost to history. Yet, this one man made a bigger contribution to mathematics than any other person in history. Euclid collated and compiled vast and disparate principles of math and geometry into a single, logical, coherent format. He set the standard for mathematical proof and rigor which is utilized even to this day. His thirteen-volume *Elements* became the standard textbook on geometry in the Western world for over 2,000 years. Every great mathematician from his own day until the 19th Century learned their trade because of Euclid’s contribution to the world.

## 2. HEROPHILOS (325-255 BCE)

Herophilos was one of the founders of the school of medicine in Alexandria. He held a view that knowledge must be ascertained upon the basis of empirical evidence, and as such, is considered one of the Fathers of the Scientific Method. His experiments in anatomy, including his pioneering and extensive dissection of human bodies, led to several incredible discoveries about the circulatory system. He was the first to determine that veins and arteries carry blood, alone (prior to this, it had been thought they carried blood, air, and water). He discovered the flow of blood through the vessels, and was the first to differentiate the veins and arteries on this criterion. He was the first physician to utilize the pulse of blood vessels diagnostically. His work was so prolific and accurate that it was oft-cited by Galen, centuries later, who is (in turn) still studied in the medical field, to this day.

## 3. ERASISTRATUS (304-250 BCE)

Along with Herophilos, Erasistratus was also a founder of the Alexandrian medical school. He, too, was keenly interested in the circulatory system, and gave the world its first description of the operations of the human heart. He also pioneered neurology, providing the earliest known descriptions of the cerebrum and cerebellum, as well as differentiating motor nerves from sensory nerves. He argued that food and water passed through the esophagus into the stomach, while others held that it passed through the trachea into the lungs. Indeed, Erasistratus is responsible for giving the trachea its modern name– before him, it had been thought to be an artery.

## 4. ARISTARCHUS OF SAMOS (310-230 BCE)

The brilliant mathematician and astronomer, Aristarchus of Samos, received his education in these sciences at Alexandria. His only surviving work attempted to determine the sizes and distances of the Sun and Moon in relation to the Earth. It’s geometry is flawless, though a small error in one datum made its conclusions wildly inaccurate. Still, others would use Aristarchus’ method to find incredibly accurate values for these questions. More amazingly, Aristarchus is the earliest person in history to suggest that the Earth is in motion around the Sun, rather than the reverse; and that the stars are so incredibly distant that we can observe no parallax from our motion.

## 5. ARCHIMEDES (287-212 BCE)

Though the details of his life are largely unknown, Archimedes of Syracuse is widely considered to be one of the greatest mathematicians of all time, and the Father of Engineering. He invented a myriad of innovative machines, including the Archimedean Screw, a type of water pump which is so simple and efficient that it is still in common use, even to this day. Archimedes’ advances in the fields of physics and math were no less incredible. He laid the foundations for statics, hydrostatics, and the mechanics of leverage. He calculated an incredibly precise value for π using an ingenious method. He developed a method for determining the area under the arc of a parabola by a summation of infinite series– an accomplishment so far ahead of its time, it bears resemblance to the Calculus that would be discovered almost 2000 years later by Newton and Leibniz.

## 6. CTESIBIUS (285-222 BCE)

Quite possibly the first head of the Museum, Ctesibius made a career out of developing wonderful machines. He found intense fascination with the elasticity of air, and began to research the subject as exhaustively as possible. As a result, Ctesibius became the Father of Pneumatics. He developed water pumps which would find use in Roman irrigation and wells, and he improved the design of the water clock, which would remain the most accurate timekeeping device for the next 1800 years. If ever you run your car out of gas, and you need to siphon some fuel from a friend’s tank, you can thank Ctesibius for developing the principle.

## 7. CONON OF SAMOS (280-220 BCE)

As the court astronomer to Ptolemy III Euergetes, Conon of Samos made a number of discoveries which would be critical to the work of mathematicians and astronomers who followed him. Conon made several advances in the study of conics, and purportedly discovered the Archimedean spiral. He wrote multi-volume astronomical treatises on eclipses and signs of the seasons. He also is the source of the name of the Coma Berenice constellation, “the Hair of Berenice,” which he coined in tribute to the Pharaoh’s wife.

## 8. ERATOSTHENES (276-195 BCE)

There exists a common myth that people all thought the Earth was flat until Columbus sailed west, in 1492, and failed to fall of the edge of the world. This is an ignominious falsity, however, which steals rightful glory away from a brilliant man, Eratosthenes of Cyrene. Not only did Eratosthenes prove that the world was round nearly 1700 years before Columbus set sail, he also formulated a remarkably accurate calculation for the circumference of the planet using only a couple of sticks and their shadows. Eratosthenes was one of the first men to realize the importance of maintaining accurate chronologies of history. His mathematical developments include advances in prime number theory which remain important, even in modern times.

## 9. APOLLONIUS OF PERGA (262-190 BCE)

One of the most important astronomers in history, Apollonius of Perga devoted a great deal of his study to discovering advances in dealing with conic sections. It is Apollonius who gave the names used even today for the ellipse, parabola, and hyperbola. He formulated deferent and epicyclic models for the orbits of the moon and planets which seemed to account for peculiar retrograde motions in the night sky. Apollonius’ work was so valuable that it has been absolutely fundamental to every astronomer to have followed him, especially the great astronomers Johannes Kepler and Isaac Newton.

## 10. HIPPARCHUS (190-120 BCE)

Perhaps the most diligent observer of astronomical data in antiquity, Hipparchus of Nicaea set the standard for recording the celestial bodies. His catalog of stars and their positions in the night sky was the first of its kind, and his keen observation led to his discovery of the precession of the Equinox. His achievements were not restricted to simply monitoring the skies, however; Hipparchus made substantial advances in mathematics and geometry. He is considered to be the founder of Trigonometry, developing tables of trigonometric data and solving difficult problems of spherical trigonometry.

## 11. HERO (10 BCE – 70 CE)

Any good list of scientists considered to be “ahead of their time” must, inevitably, include Hero of Alexandria. Mathematician, inventor, and prolific teacher at the Museum, Hero provided the world with numerous contributions. In mathematics, he developed new methods for determining square roots and finding the area of a triangle. In physics, he continued Ctesibius’ research on pneumatics and fluid pumps, eventually inventing the first steam engine. Most amazingly of all, in the 1st Century CE, Hero pioneered the construction of automata– the forerunner to modern robotics– including his design of a programmable, automatic wagon and his construction of an entirely automated theater play which ran ten minutes in duration. And he did all this 2000 years before the first modern computer was built!

## 12. PTOLEMY (90-168 CE)

As Euclid was to mathematics, Claudius Ptolemy was to astronomy. He compiled immense amounts of astronomical information together into a single work which began from first principles and built upon its previous knowledge until encapsulating all of the foremost knowledge of the Celestial Sphere of his day. Though he called these books his “Mathematical Treatise,” they quickly became known to the Greek world as “The Great Treatise,” due to their unparalleled brilliance. Today, the work is known primarily due to its preservation and usage by later Arabic astronomers, and so we refer to it as the *Almagest*. The thirteen books of the *Almagest* were so incredible that they remained the most accurate mathematical description of the motion of the heavenly bodies for almost 1500 years, until they were superseded by the work of Johannes Kepler.

## 13. DIOPHANTUS (201-285 CE)

Often referred to as the Father of Algebra, Diophantus is another in the long line of Alexandrian mathematicians whose work was so massively influential that it remains in use, today. His principle surviving written work is known as the *Arithmetica*, a sort of collection of his research on a multitude of mathematical problems. Diophantus was the first Greek mathematician to recognize that fractions are, themselves, numbers and not simply relationships between two other numbers. He developed new methods of notation and symbology with which mathematics became more precise and efficient, and which foreshadowed modern algebra. He discovered incredible methods of analysis, and greatly furthered the progress of number theory, in his time.

## 14. PAPPUS (c.290-350 CE)

As the flame of Western mathematics was dying, in the 4th Century Roman Empire, Pappus of Alexandria remained a glowing, hot coal. Unfortunately, he was underappreciated by his peers and much of his work has been lost, but that which remains is prolific. His *Synagoge* covers a wide range of mathematical topics, from recreational math to projective geometry. Indeed, one theorem which Pappus formulated in this latter field remains in use, today, known as Pappus’ hexagon theorem. We are only able to give a date to his life thanks to his calculation, prediction, and observation of a solar eclipse, which we now know occurred on October 18, 320 CE.

## 15. THEON (c.320-395 CE)

Of all the men I have listed, Theon of Alexandria was the least innovative. He did not give us any breathtaking or groundbreaking new theorems or discoveries. However, Theon’s contributions to history are still incredible. He was the consummate professor, and one of the last teachers at the Museum before its destruction at Christian hands in 391 CE. As such, he was incredibly well-read, and had mastered knowledge of a wide array of the mathematical text in Alexandria’s Great Library. His great contribution to the world was in his preservation and dissemination of these texts. His editions of Euclid’s *Elements *and *Optics*, as well as his commentaries on Euclid’s *Data* and Ptolemy’s *Almagest* and *Handy Tables* remain some of our only and prime sources for these works in their original Greek, even today.

## 17. HYPATIA (c.370-415 CE)

The daughter of Theon, Hypatia of Alexandria is a painful example of how one of history’s most fantastic minds can be almost entirely lost to the world. Almost none of her works survive, and that which does survive is hotly contested among scholars. Hypatia lived at the end of the 4th Century and the beginning of the 5th Century, CE. She surpassed her father in mathematical skill, mastering the advanced works of Apollonius and Diophantus, and providing commentaries on each. She appears to have had a hand in editing her father’s work on the *Almagest*, and may have discovered an efficient new method for performing long division. She was also a brilliant philosopher, and became head of the school of Plotinus in Alexandria, whereupon she taught everyone who had an ear to learn about Plato and Aristotle and the other great philosophers.

Hypatia eschewed normal gender roles, and became highly influential in the politics of her world. Her advice was highly prized by the governor of Alexandria, Orestes, and by her former student Synesius, Bishop of Cyrene. She was widely lauded for her virtue and her acumen, and she did not shy away from speaking at political assemblies. All this earned her the ire of Cyril, Bishop of Alexandria, and the firebrand Christians who followed him. As Cyril was embroiled in a bitter feud with Orestes, many of the bishop’s zealous follower came to blame Hypatia for Orestes’ refusal to submit. In 415 CE, a mob of angry Christians intercepted Hypatia on her way home and dragged her to the church called Caesareum, where they stripped her naked, beat her to death with stone tiles, and tore her body limb from limb before casting it to the flames.

## The Most Important City in History

From it’s inception in the 280’s BCE to its destruction in 391 CE, the Museum at Alexandria was an unparalleled center of learning and discovery in the world. The contributions of its teachers and its students to geometry, number theory, physics, engineering, astronomy, and medicine are absolutely integral to the study of modern sciences. Alexandria’s research and its Great Library taught the world the value of acquiring knowledge simply for knowledge’s sake. If Alexander had not founded his great city by the sea, if Ptolemy I Soter had not commissioned its incredible Museum, or if the Great Library had never stocked its shelves, we may never have become the world that we are, today.