Mathematician, Astronomer, Geographer, Writer, Poet, Musician, Scholar (c.246 BC – c.194 BC)

Eratosthenes was one of the greatest sages of ancient Greece. He was headmaster of the Library of Alexandria and the founder of geography as a science as we know it today. His most famous achievement was the measurement of the circumference of the Earth.

He was born in Cyrene, a Greek colony of North Africa. He was 11 years older than Archimedes, with whom he was good friend. Eratosthenes studied mathematics and astronomy in the Academy of Athens under his teachers Ariston and Arcesilaus. He then continued his studies in Alexandria under his teacher Callimachus, where he remained and worked for the rest of his life. He was one of the many Greek intellectuals who comprised the staff of the Library of Alexandria, the greatest spiritual center of humanity as the time, including Ctesibius, Hipparchus, Apollonius of Perga, Apollonius of Rhodes, Conon, Aristarchus, Heron and Philon of Byzantium. He served as the third headmaster of the Library of Alexandria.

Eratosthenes was a polymath; he was nicknamed “Pentathlos” because he excelled in numerous fields such as mathematics, astronomy, physics, geography and music. By far his most notable contribution in the sciences is the measurement of the circumference of the Earth, a feat that is recorded for the first time in ancient history. Knowing that at the river Syene (modern Aswan), 500 km away from Alexandria, during the summer solstice, the sun’s rays fall vertically at noon and that at the same date and time at Alexandria, the rays fall with an angle of 7,2 degrees, Eratosthenes calculated the distance between the river and Alexandria at about 820 km. By accepting that the sun rays are parallel to each other and that the difference in the geographic latitude between Syene and Alexandria is equivalent to the angle the sun rays form during that time, Eratosthenes, using a rod and its shadow calculated the equatorial length of the Earth at 41.000 km, with a negligible error of 1000 km, because he miscalculated the distance of Alexandria and Syene instead of 800 km.

Eratosthenes was a prolific writer. He wrote several books ranging from mathematics and astronomy to poetry and philosophy, most of which do not survive today. In his treatise Catasterism he compiles a catalogue of constellations and their respective stars, calculates the Earth’s polar diameter with great accuracy as well as the distance of the Earth and the Sun. One of his most famous contributions to mathematics is the Sieve of Eratosthenes, a method for finding prime numbers, of which Eratosthenes is the inventor. He also solved the Delian problem, the doubling of the cube in his treatise Mesolavos.

The scientific foundations of geography were laid by Eratosthenes. In his now lost treatise Geographica, he presents the history of geography, mathematical and physical geography and perigraphic (discriptional) geography, including oeconomic and ethnographic elements. Furthermore, he created a world map as well as a calendar called Chronological Table, which covered 1076 years starting from the Fall of Troy, featuring most significant scientific and historical events recorded at the time for each date, regarded as a groundbreaking undertaking in the history of sciences. In philosophy, Eratosthenes was concerned mostly with ethics, poetry inspired from astronomy and comedy plays.

Eratosthenes had the rare privilege of being recognized as a great scientific mind during his own time. He was praised for his wisdom by notable intellectuals of his time such as Archimedes and Ptolemy Euergetes. The fact that he calculated the Earth’s circumference using nothing but geometry, a sacred science to the Greeks, proves Eratosthenes’ wisdom and justifies his influence on the ancient world and the Western civilization.


  1. “Eratosthenes”. Helios New Encyclopaedic Dictionary. Passas, I. Athens: 1946. Print.
  2. Georgakopoulos, Konstantinos. Ancient Greek Scientists. Georgiades: Athens, 1996. Print.
  3. The Editors of Encyclopaedia Britannica. Eratosthenes. Encyclopaedia Britannica. Web. July 15, 2018.

Diodorus of Sicily


Historian, Writer (1st century BC)

Diodorus Siculus was one of the most famed historians of antiquity, widely considered today as a pioneer in historiography. His massive work Bibliotheca Historica comprises 40 books and spans the universal history of mankind, from the mythical era until the age of Julius Cesar. With the majority of the work having been destroyed, Diodorus nevertheless presents himself as a master of his art and an authority on world history.

As his name implies, Diodorus was born in Sicily and was active primarily in Rome. A restless spirit, he dedicated 30 years risking his life and subjecting himself to dangerous feats in order to accumulate the best material needed to compile his magnum opus, travelling to various parts of Europe, Asia and Africa. In Rome he learned Latin and researched the libraries, collecting information that could be found elsewhere.

Years of meticulous research resulted in the compilation of the largest history treatise that existed at the time, the Bibliotheca Historica. Diodorus follows a chronological order, describing not only the most significant events that occurred during each year, but also the geographical relations, the culture, the customs and the traditions of peoples. Furthermore, he names notable individuals in the fields of arts and poetry, not solely on politics and military affairs. Even though he did not possess the experience and the skill of his predecessors Thucydides and Xenophon, Diodorus adheres to the scientific method of historiography.

Bibliotheca Historica is divided into 3 parts. The first part covers the mythical era up until the fall of Troy. The second part contains the history from the fall of Troy until the death of Alexander the Great. The third part picks up from the second part ends and ends with the conquests of the Romans against the Britons. Out of the 40 books in total, only the first five and the second decade survive in their complete form.

In the remaining surviving books, Diodorus writes about the following: the Egyptians, the Babylonians, the Atlantians, the Assyrians, the Scythians, the Hyperboreans, the Persians, the Indians, the Arabs, the Africans, on the Greek mythology, the Greek islands and the Greek colonies, Xerxes’ campaigns against Greece and Cyprus up until the battle of Syracuse, the 30 Tyrants of Athens until the fall of Rome by the Galatians, King Philip’s rule of Macedonia, Alexander’s conquest of Asia, his death and the Diadochi up until the contemporary events of Diodorus.

Overall, Diodorus’ ambitious undertaking of writing down the entire history of mankind from the beginning until his contemporary times places him among Greece’s most acclaimed historians Herodotus, Thucydides, Xenophon and Polybius. His writings are the only surviving source of certain parts of history that are considered as landmarks at a time when the Greek history was synonymous to universal history.


  1. “Diodorus Siculus”. Helios New Encyclopaedic Dictionary. Passas, I. Athens: 1946. Print.
  2. Badian, Ernst. Diodorus Siculus. Encyclopaedia Iranica. December 15, 1995. Web
Diodorus of Sicily



Lawmaker (c.650 BC – c.600 BC)

Draco was the lawgiver of Athens, the first statesman who wrote down the laws of the city since the mythological era when Thesaeus reigned as king of Athens. He was a political reformer who changed the political system of Athens, implementing laws which were very strict at the time. Revered by many, Draco was considered a very important statesman in the history of Athens and is now among the greatest lawgivers of antiquity, alongside Solon and Lycurgus.

Before Draco, Athens’ laws were not written anywhere. Even though they existed, they were not available to the public hence citizens could not refer to them anywhere. Athens had been experiencing a period of long political decline, social instability and a crisis of values. It was around 621 BC when Draco was assigned to write down the laws of Athens so that they become available to the public. In addition, Draco passed down significant reforms of the law, implementing changes in criminal law and private law.

Draco’s laws were originally written on wooden tablets before being chiseled on stone slabs and placed in public view. They were said to have been written with human blood. Even though most of his laws are not known, Draco’s legislature was extremely strict, punishing even the simplest of crimes, such as theft being punished with death. His most well-known was the law of homicide, which was the only one kept by Solon when he succeeded Draco as lawgiver of Athens. Among some of Draco’s laws were the implementation of the Ecclesia of the people, the passing down of political rights to all men who could be mobilized for war, the reduction of the jurisdiction of the Areios Pagos, the court of Athens concerning the preservation of laws and the ability of citizens to report the decisions of the Areios Pagos as unfair.

In spite of their severity, Draco’s laws made every citizen of Athens equal before the law, regardless of their wealth or status. He succeeded in stabilizing Athens’ political and social condition for almost half a century and highlighted the importance of discipline, which was eclipsing from the Athenian society. His laws combated crime and imposed order to an astounding degree. As a predecessor of Solon, Draco contributed significantly to the re-establishment of democracy in Athens and while his laws may have only lasted for almost half a century, they were necessary for putting Athens back on its former track.


  1. “Dracon”. Helios New Encyclopaedia of the Sun. Passas, I. Athens: 1946. Print.
  2. Ο Νομοθέτης Δράκων. Αρχαίων Τόπος. November 16, 2017. Web
  3. Dhwty. The brutal Draconian laws of ancient Greece. Ancient Origins. November 20, 2014. Web.


Mathematician, Engineer, Inventor (285 BC – 222 BC)

Ctesibius was a mathematician and engineer, founder of the Polytechnic School of Mathematics and Engineering of Alexandria. Together with Philon of Byzantium and Heron of Alexandria, he is one of the initiators of the automata as well as one of the greatest inventors of antiquity together with Archimedes.

Ctesibius worked in Alexandria during the Hellenistic era, when it was ruled by the Ptolemy dynasty. Alexandria was humanity’s greatest spiritual center at the time, which attracted scholars, mathematicians, artists, astronomers from all over the Greek world. Great minds such as Aristarchus, Conon, Apollonius of Rhodes, Apollonius of Perga, Hipparchus and Philon of Byzantium acted there. Ctesibius was part of this group of scientists who comprised the Museum of Alexandria, right next to the famous Library of Alexandria. Though not proven, Ctesibius is thought to have been the first headmaster of the Museum.

He is considered as one of the founding fathers of the automatic machines, as well as the Father of Pneumatics, the science that uses compressed air for operating machines. Ctesibius wrote the very first treatise on pneumatics and their application in pumps, but unfortunately none of his writings survive, although they are mentioned by numerous scientists such as Vitruvius, Athenaeus, Heron of Alexandria and Proclus. His writings include Pneumatica, Hypomnemata Mechanica, Velopoeetica and Memoirs.

The machines he invented were numerous. They ranged from water pumps, cranes and weapons to automatic machines, clocks and musical instruments. Below are listed some of his most notable inventions:

  • The Hydraulic Clock, a marvelous automation that could operate continuously without human intervention. The machine operated with a series of containers one on top of the other, filled with water, a float and a statuette holding a pointer, which could show the exact hour and date on a rotating drum that contained a trace of hours of day and night.
  • The Musical Mirror, a mirror that could be adjusted in height, produced music through mechanism of a closed vertical tube inside of which were musical pipes. The movement of the weight caused pressure to increase within the pipes thus producing the desired notes. It was used in his father’s barber shop.
  • The piston force pump was a double suction force piston pump used for fluids. It was also known as siphon. It operated with the help of pivoted levers, handles, two vertical cylindrical containers and valves. The device is still used extensively to this day by firefighters, albeit in different forms.
  • The Hydraulis, constructed during the 3rd century BC was the very first keyboard instrument ever created. It used water and compressed air, the latter delivered through a series of pipes that produced music, depending on the 24 keys pressed on the keyboard. The Hydraulis is the forerunner of the church pipe organ used today. A contemporary replica of the Hydraulis survives to this day.
  • Cranes that could lift very heavy objects; worked using a system of compressed water.
  • Cannons that operated with compressed air and hydraulic catapults.
  • Automations for entertainment, such as a singing cornucopia and a statue that stood up and sat down continuously using a cam-operated mechanism. Although a simple act, the statue produced a lot of excitement, at a time when the power of the toothed gear was being researched.

Ctesibius’ works deeply influenced the Romans and the scientists of the Renaissance. Modern day scholars have estimated that Ctesibius and the Greeks of his era were 100 years away from inventing the steam engine. Had this occurred, the Industrial Revolution would have begun almost 2000 years ago in Greece, instead of the 18th century. Today, Ctesibius’ inventions have been recreated and most of them still in use.


    1. Ctesibius of Alexandria. Web.
    2. Georgakopoulos, Konstantinos. Ancient Greek Scientists. Georgiades: Athens, 1996. Print.
    3. Kotsanas, Kostas. Ancient Greek Technology The Inventions of the ancient Greeks. Kostas Kotsanas: Pyrgos, 2013. Print.
    4. Πώς οι αρχαίοι Έλληνες μηχανικοί έφθασαν ένα βήμα πριν από την ατμοκίνηση, χιλιάδες χρόνια πριν από την Βιομηχανική επανάσταση και την εφεύρεση της ατμοκίνητης αντλίας το 1776. Κτησίβιος, Φίλωνας και Ήρωνας ήταν οι κορυφαίοι εφευρέτες. Μηχανή του Χρόνου. Web.



Hippalus the Governor

Geographer, Explorer (2nd century BC – 1st century BC)

Hippalus was a navigator, cartographer, geographer and meteorologist who lived in the 2nd and 1st century BC. He is mostly known for his voyages in Arabia and India, as well as being a pioneer in meteorology. His travels greatly helped the Roman Empire expand its trade to the Eastern world. While he is mentioned in Ptolemy, Strabo and Pliny’s works, Hippalus’ position in history is not fully appreciated.

Hippalus travelled from Greece to Egypt and from there to India. As a meteorologist he made numerous important discoveries. The most significant one was the existence of the monsoons, periodic winds that blew in the Indian Ocean, which changed direction from north to south one half of the year and south to north the other half. These winds are termed Hippalian winds. Hippalus was the first to utilize these winds to cross the Indian Ocean on open sea, instead of next to the shore, as was typically done by sailors. Thus, his journey was much shorter in duration.

Soon after his discovery, ships started implementing the use of the monsoons as Hippalus had done, thus creating a new trading route between India and the Roman Empire. This secured a faster and safer route for the ships, free of pirates.

As a cartographer he drew maps of the shores of the Red Sea, as well as its ports. In the book Periplous of the Erythraean Sea, he is described as the first man who discovered the route from the Red Sea to the Indian peninsula via the Indian Ocean. He wrote books, none of which survives today.

His influence in the Romans and Greeks is evident from the fact that Ptolemy, one of the greatest astronomers of antiquity named the Indian Ocean Hippalian Sea in his writings. Today, a crater on the moon bares his name.


Georgakopoulos, Konstantinos. Ancient Greek Scientists. Georgiades: Athens, 1996. Print.

Hippalus the Governor



Philosopher (c.540 BC – c.470 BC)

Parmenides was a Pre-Socratic philosopher from Elea. He is called the Father of Metaphysics, because he was the first who spoke about the nature of existence. Considered as one of the most influential figures in the history of philosophy, Parmenides set the principles of ontology for future Greek and international philosophers.

Initially involved with politics, Parmenides made laws for his country, until resigning to focus on philosophy. We do not know how many books Parmenides wrote, but by far his most complete one is On Nature. It is a poem, of which only fragments survive, divided into 3 parts: The first part, also named Poem describes a man’s spiritual inner journey in search of enlightenment. In the second part named Alethia (Reality), Parmenides deals with all that is real. The third and final chapter named Doxa (Opinion) deals with the erroneous ideas of man and is presented as an antithesis to the second part of the poem.

A basic concept of Parmenides’ philosophy is the being. The being, according to the philosopher, has neither beginning nor end, possesses inseparable completeness, is immovable, inalterable and indivisible. Furthermore, the being is eternal and as such, past, present and future overlap. Similarly to Heraclitus, Parmenides distrusted the senses, stating that while these change, the being does not. For him, the only reality that exists is the one we can perceive with our intellect. Reality is made of one substance, the same substance from which it came, and we, who inhabit this world, share the same substance.

Understanding Parmenides’ highly complex philosophy has proven to be a very difficult task, leaving modern thinkers and scholars perplexed as to how to interpret his theories. The enigmatic nature of his incomprehensible treatise also challenged the Pre-Socratics, few of whom understood what Parmenides really meant. His influence on his successors was, nevertheless, significant and included Melissus of Samos, Zenon of Elea and Plato, who is said to have revered him for the depth of his thought. Plato also wrote a treatise after him. The concept that intellect identifies existence was later picked up by Descartes, who said “I think, therefore I am”.


  1. DeLong, Jeremy C. Parmenides of Elea. Internet Encyclopaedia of Philosophy. Web. Retrieved on April 29, 2018.
  2. Mark, Joshua J. “Parmenides.” Ancient History Encyclopedia. Ancient History Encyclopedia, 28 Apr 2011. Web. 30 Apr 2018.
  3. Pleures, Konstantinos. Greek Philosophers. Hilektron Publications: Athens, 2013. Print.



Sculptor (4th century BC)

The greatest sculptor of antiquity together with Scopas and Lysippos. Praxiteles earned widespread fame for his creations, which decorated numerous cities in Greece. He influenced the art of sculpture more than any other sculptor in the world.

His father Cephisodotus was also a sculptor and a teacher of Praxiteles. His aunt was married to Phocion, who was a student of Plato. This presumably allowed Praxiteles to not only have connections with the political upper-class of Athens, but also delve into Platonic philosophy, which he applied to his art.

Praxiteles was the one of perfected sculpture. His sculptures were primarily idols of Gods, depicted in human form. It is estimated that the minimum number of sculptures he created were 70. Some of them were commissions for other city-states of Greece. Praxiteles was also a teacher of sculpture.

Among his most famous sculptures, widely known to this day are the following:

  • Leto, Apollo and Artemis depicted on a series of slabs excavated in Mantineia, with Apollo battling against Marsyas in the presence of the Muses.
  • Hermes and the infant Dionysus, regarded as Praxiteles’ most recognizable work. The sculpture was excavated in Olympia. Hermes is holding an infant Dionysus with his left hand supported on a tree bark. It has come to be known as Hermes of Praxiteles.
  • Aphrodite of Cnidus was the first statue of a naked Aphrodite ever created and was the one that skyrocketed Praxiteles’ fame in the Greek world due to its daring nature at the time. It is accepted as one of Praxiteles’ most beautiful sculptures. The statue was bought by the Cnidians, who held it on display in their hometown.
  • Cupid (Heros) depicted as a young boy with wings. It was found in Propontis, Asia Minor.
  • Apollo Sauroktonos, a statue showing Apollo as an ephebe pointing an arrow against a lizard. The statue has not survived. Depictions of it were found on the coins in the city of Mysia in Asia Minor.
  • The marble triad of Cupid, Phryne and Aphrodite where Cupid, a personification of the Platonic idea, suffers from love (heros). The statue was discovered in Thespiae.

Some other of his masterpieces include the bronze Resting Satyre, the Petworth Head of Aphrodite, the head of Euvuleus,the statue of an enthroned Leto, made of precious stone in Lycia and Artemis of Antikyra. In addition, Praxiteles built the statues that decorated two of the Seven Wonders of the Ancient World: the Mausoleum of Halicarnassus and the Temple of Artemis in Ephesus.

Praxiteles’ unparalleled skill remained unsurpassed in time. His statues were literally vessels by which the Gods descended to the physical field of man. His, as well as other great sculptors’ statues played an important role in the meditation (Διαλογισμὸς) of the ancient Greeks. Today, his works adorn museums inside and outside the Greek boundaries.


  1. “Praxiteles”. Helios New Encyclopaedic Dictionary. Passas, I. Athens: 1946. Print.
  2. Πραξιτέλης. Εγκυκλοπαίδεια Μείζονος Ελληνισμού.