The Hellenistic geographer Era, Who was the first to use the different shadow angles projected by the sun on the two cities, was mentioned in the astronomical achievements of the Hellenistic era, and he was the first to successfully calculate the correct diameter and circumference of the earth. In fact, Eratostini was not only in astronomy, but his contributions to geography were far more than that.
In fact, the English Geography of "geography" is derived from the ancient Greek γεωγραφία (that is, the description of the earth), and Eratostini was the first to use this word, so Eratosthenes was rightly called the father of geography by the West.
Before Alexander the Great, large areas of Central Asia were ruled by the Persian Empire, and during this time, some Greeks were able to travel within Persia and record what they saw and heard in writing. One example is the Greek traveler Syracuses (Greek mathematician and geographer. Born in Caria in present-day Turkey).
In the 5th century BC, Syracuse was the first Greek to reach India and Central Asia, and wrote the book Periplus, which recorded the customs and political geography of large areas of Asia.
Herodotus, the "father of history", also traveled to the Near East and wrote a book called History, which described the world known to the Greeks at that time, including Europe, Africa and Asia, but Herodotus did not believe in the existence of the northern and southern hemispheres and the equator, and falsely exaggerated the length and breadth of Europe, such as the length of Europe as the sum of Africa and Asia.
Herodotus (c. 480 BC – 425 BC)
Alexander's conquest of the Persian Empire in the 4th century BC meant that greeks could travel freely over large areas of the world and bring back to Greece what they saw and heard everywhere. Eratostenes used the geographical novelty acquired by the Greeks during this period, as well as travelogues preserved in the Library of Alexandria in Egypt, to construct a model of the known world.
According to the Hellenistic geographer Eratosthenes, the map of the world known to the Greeks at that time
Eratostini wrote a three-part book, Geography, in which he divided the world into 5 climatic zones:
In his first book, Eratostini proposed that the Earth was an unchanging sphere that changed only one layer of the earth's surface, and he had theorized that the Mediterranean Sea was once a huge lake, and that it was connected to the sea at some time after it was opened in the Western Strait of Gibraltar.
In the second book he used mathematical principles on top of geography and estimated the circumference of the Earth.
In the third book, he lists the countries of the world known to the Greeks at that time, and for the first time used vertical and horizontal grids, that is, longitude and latitude to measure the entire world, because of his invention, Greek travelers could finally obtain accurate coordinates of remote locations and the distances between places.
Eratostenes used his data to produce the first projection map in human history, centered on the Mediterranean Sea, covering everything from Gibraltar to the Caspian Sea and Sri Lanka, from Britannia to Ethiopia. Eratostini also accurately measured the deflection angle between the equator and the ecliptic to within 7 minutes, and calculated the tilt angle of the Earth's axis to 23.5 degrees, inferring that the appearance of the four seasons came from the inclination of the Earth's axis, which was quite accurate at the level at that time.
Unfortunately, Eratosthenes' original geography has been lost, and we can only glimpse parts of the original geography from the works of Pliny the Elder, Polybius, and Strapo.
The 2nd-century Hellenistic astronomer Hipparchus, mentioned in the previous part, wrote three books criticizing Eratostini, and now we can know his reasons and arguments against Eratostini through Strapo's writings.
Hipparchus criticized Eratosthenes' writings for its contradictions and inaccuracies in determining the exact coordinates of a place.
Hipparchus believed that only astronomical observations and triangulations could correctly calculate the correct coordinates of a place, and he first used a grid with scales and observations of stars to calculate latitude, and used the method of observing the same lunar eclipse at different locations to calculate longitude. Using this method, he estimated dozens of locations, including Athens, Sicily, and the southernmost coordinates of India.
In addition, Hipparchus further calculated that the tilt of the Earth's axis was 23 degrees and 40 points, which was only 3 points different from the correct value of 23 degrees and 43 points in the 2nd century BC. At the same time, Hipparchus challenged the widely accepted theory that the Atlantic, Indian, and Caspian oceans connected the oceans, and extended the boundaries of the known world to the equator and the Arctic Circle.
The early Hellenistic navigator Pisias (350-285 BC), the first Greek navigator to sail around Britannia, sailed around 325 BC to the remote northwestern corner of Europe, bringing back first-hand descriptions of the Germanics and recording for the first time the phenomenon of polar diurnal night (i.e., half-year daylight and half-year night in the Arctic Circle), and he was also the first to personally observe the midnight sun and the ice floes at sea.
The voyage of Pisias
It can be inferred that Pisias once entered the Arctic Circle and may have visited Norway or even Iceland, representing the farthest place ever traveled westward in the Hellenistic era. He was also one of the first to speculate that the moon caused tides, and that the Baltic Sea and the local amber were abundant.
In addition, the ancient Greeks also found fossils, and the philosopher Xenophon of the 6th to 5th centuries BC correctly deduced that they were the remains of ancient creatures.
A map of the world made according to the coordinates listed in the Ptolemaic era represents the culmination of Greco-Roman geographical achievements
The writings of Aristotle, Opholius (ancient Greek poet and grammarian), Plutarch, Elianus and others in the late Roman era have all circulated legends about fossils, and have made fairly accurate observations and inferences about the types of fossils, the extinction of organisms, the length of time in extreme antiquity, stratigraphic lithology, and seismology. Although geology did not blossom in the Hellenistic era like other studies, the observations of geology by Hellenistic scholars can be called forerunners.
The island of Britannia reconstructed in Italy in 1490 based on Ptolemaic sources
From the above discussion, we can see that the Greeks' geographical understanding of the world ended in Bactria and India. Since this is the case, I believe many friends will ask a question, when did Westerners begin to know about our existence in China?
We know that the Greco-Roman geographers Strapo, Pliny the Elder, and Ptolemy of the Roman era from the 1st century BC to the 2nd century AD knew that there was a state called Cyris east of India.
Serris means Silk Country, Silk Country people, is the Warring States to the Eastern Han Dynasty ancient Greek and Roman geographers, historians of the country and ethnic group associated with silk, generally believed to refer to China at that time or near China. Derived from Wikipedia.
Ptolemy even positioned Snapolis, the capital of Serris, which may have been ancient Chang'an, to 119.5 degrees east longitude and calculated that Snapolis and Alexandria, Egypt, had an 8-hour time difference.
Of course, there are a lot of myths and fantasies about the Greeks and Romans' perception of Cyris, including its race and property, and there is still great controversy about whether Cyris is really equivalent to China in the real world.
According to the records of China's "Later Han Shu • Biography of the Western Regions", during the Han Dynasty in China, it was already known that there was a great empire in the West, "Great Qin", which was similar to itself, and recorded the deeds of The Great Qin King An Dun (most likely Antony among the Five Wise Emperors) sent envoys to China to exchange with each other in the ninth year of Emperor Huan's reign (166 AD).
Although most later generations believe that the Great Qin envoys were not official envoys, but private merchants pretending to be, this incident shows that more than a thousand years before Marco Polo, at the latest in the Eastern Han Dynasty, the two ancient powers may have been able to travel long distances to communicate with each other and influence each other.
Especially in recent years, historians have begun to pay more attention to this possibility. In recent years, archaeological work on the Terracotta Warriors of Qin Shi Huang in Xi'an has found pottery figurines with a strong Hellenistic style, as well as stone columns in hellenistic style found in the Western Han Dynasty Nanyue Palace Office in Guangzhou (about 200 BC); many antiques with strong Chinese art styles from the same period have also been found in the West.
Hellenistic style stone pillars found in the Palace Of The Royal Palace of Nanyue were built around the end of the 3rd century BC to the beginning of the 2nd century BC. (Photo: Guangzhou Daily)
Above and below: The dragon in the Persian miniature painting has a strong Chinese art style.
All of this points to the possibility that as early as the 3rd century BC, the two great civilizations of the East and the West had already exchanged many times through Bactria, the closest to China. But if this theory is true, then why did Eratostini and Hipparchus say nothing about it?
Was the exchange between the ancient Eastern and Western civilizations at the national level, or was it only indirect exchanges between the nationalities? If it is the latter, it may explain the phenomenon that Greek culture can have a place in the Central Plains, while the existence of China is not known to the Greeks. Of course, this point is still speculative, and it is still up to archaeologists and historians to continue to work on it to have a definite answer.