Claudius Ptolemy: biography and contributions of this researcher.

A summary of the life of Claudius Ptolemy, famous researcher of Hellenistic Egypt.

Claudius Ptolemy was a Greek astronomer, mathematician and geographer born in Egypt when this country was a Roman province. The contributions of this scientist were fundamental, especially during the Middle Ages and early Renaissance.

We do not know much about the life of Ptolemy, but some of his works have transcended, especially thanks to the medieval Islamic intellectuals who echoed the valuable knowledge that Claudius Ptolemy was building throughout his life.

We will now talk a little about the life of this researcher of Ancient Greece by means of a short biography of Claudius Ptolemy and we will see what his work was and why he was so important.

Short biography of Claudius Ptolemy

Claudius Ptolemy was a Greek astronomer, geographer, mathematician and astrologer born in Egypt in Classical Antiquity.. He is known for his proposal of the geocentric model of the universe, known as the Ptolemaic system, which had a notorious repercussion among Christian and Muslim intellectuals of the Middle Ages and part of the Renaissance. He is also credited with having created the first maps with coordinates of the main places on the planet in terms of latitude and longitude.

His ideas and theories of geography and astronomy were very important until the 16th century, when Copernicus formulated his theory that the planets revolved around the Sun, including the Earth, an idea that until that time was just the opposite. Ptolemy's work is strongly influenced by Hipparchus of Nicaea, a Greek astronomer who lived several centuries before him.

What do we know about the life of Claudius Ptolemy?

It is not very well known when Claudius Ptolemy was born. There are sources that point out that it must have been around 85 AD, but other authors consider that it was in the year 100 AD. This doubt persists, and will probably never be resolved, since there are not many historical records detailing what became of his life.

It is estimated that the place of his birth was in Upper Egypt, specifically in the city of Ptolemaida Hermia, located on the right side of the Hermia River.located on the right side of the Nile River, near the present Menshiyeh. This was one of the three cities founded by the Greeks in northern Egypt, the other two being Alexandria and Naucratis.

There is not much biographical information on Ptolemy, but it can be stated that he worked and lived all his life in Egypt. The sources that provide something of the life of Claudius Ptolemy point out that he was dedicated to astronomy and astrology, mainly. It is also known that he was interested in mathematics and geography, and that he did numerous works on the knowledge and methods he possessed about these disciplines.

We also do not know too much about his death, although it is believed to have occurred around 165 AD in the city of Alexandria, where he worked as one of its librarians and compilers of knowledge. If it is true that he was born in the year 100 A.D., he would have died when he was 69 or 70 years old.

Ptolemaic empiricism

One of the most remarkable things about the work of Claudius Ptolemy was that he he carried out his studies with an emphasis on empiricism.. He applied this approach to all his work, which set him apart from other scientists of the time.

Many of the descriptions that Ptolemy made did not seek to be real and exact replications of the phenomena he studied, but rather he tried to understand and justify why they occurred from what he observed.

Influence of Hipparchus of Nicaea

It is difficult not to talk about Hipparchus of Nicaea when discussing the life of Claudius Ptolemy, since this Greek geographer, mathematician and astronomer greatly influenced the work of Ptolemy. As it happens with Claudius Ptolemy, we do not have too many data about Hipparchus, knowing that he lived between 190 and 120 BC. The vital information of Hipparchus of Nicaea we know thanks to the historian and geographer Strabo and Ptolemy himself.

Claudius Ptolemy described on several occasions the achievements and discoveries of Hipparchus and attributed many inventions to him. Among these inventions was a small telescope that was fundamental to improve the process of measuring angles, an instrument by means of which it was possible to establish that the period of the solar year lasted 365 and 6 hours, an approximation very close to what we have today of the length of a natural solar year (365 days, 6 hours, 9 minutes and 9.76 seconds).

The influence of Hipparchus on the work of Ptolemy was also notorious, thanks to the first publication that the Grecian thanks to the first publication that the Greek-Egyptian made: the Almagest.

His time at the Library of Alexandria

During most of his life, Claudius Ptolemy dedicated himself to astronomical observation in the city of Alexandria.. This he did between the reigns of the emperors Hadrian (117-138 AD) and Antoninus Pius (138-171 AD).

Claudius Ptolemy is considered to be is considered part of the so-called Second Period of the Alexandrian School.The Roman Empire had expanded throughout the Mediterranean and its environs.

Although there is not much information about it, it is believed that Claudius Ptolemy did a great work in the Library of Alexandria. This building was one of the greatest centers of knowledge of the Ancient World, and therefore Ptolemy had the opportunity to access great texts of astronomers and geometers before his time.

If this is true, Claudius Ptolemy would have been the one in charge of compiling and systematizing in charge of compiling and systematizing all that knowledge, especially those referring to astronomy.especially those related to astronomy, data that could date back to the third century BC. He also made multiple contributions in the field of astronomy, especially regarding the movement of the planets, thanks to the substantial knowledge he acquired in his work as a librarian.

The Almagest

While working in the library in Alexandria, Claudius Ptolemy wrote a book that would eventually become his most important work and greatest contribution to astronomy from a mathematical perspective: the Almagest.. It was originally entitled "Hè megalè syntaxis" (The great composition) in thirteen volumes, however, with the passage of time it would eventually receive the name by which it is known today, much more emblematic.

"Almagestum" is a word that comes from the medieval term "almagestum" which, in turn, derives from the Arabic "al-magisti", translatable as "the greatest". The reason it is now so called is that, despite being originally written in Greek, it aroused much interest in the medieval Islamic world. The caliph al-Mamun (786-833) had it translated into Arabic in 827, and it would eventually reach Christian Europe in Arabic.

His works on astronomy and astrology.

The Almagest was inspired by the study of Hipparchus of Nicaea while Ptolemy was working in the Library of Alexandria. In the work, reference is made to the Earth being the center of the universe and that, for this reason, it remains immobile.. Around our planet revolve the Sun, the Moon and the stars and, according to Ptolemy, all celestial bodies draw perfectly circular orbits. In this work he also tells us about the measurements of the Sun, the Moon and a set of celestial bodies that amounted to a total of 1,028 stars.

In ancient times it was very common for people to believe that personality was influenced by the position of the Sun, the Moon or other celestial bodies at the time of birth. at the moment of birth. Astrology was a deeply rooted belief and shared even among the scientific elites of the time, who came to consider it a science. Ptolemy was no exception.

This Greek-Egyptian mathematician wrote a famous treatise on astrology called "Tetrabiblos" (Four Books), an extensive work in which he discusses the principles governing astrology and horoscopes. In it, he he defended the theory that ailments, diseases and other health problems were caused by the influence of the Sun, the Moon, the stars and the planets.. Each star had an influence on specific parts of the body.

His contributions to optics

One of his most interesting works is the so-called "Optics", composed of five volumes in which He dealt with the theory of mirrors and also with the reflection and refraction of light, and he was a pioneer in this aspect, since few scientists considered luminous and visual phenomena as he did in Greco-classical Egypt..

He took these phenomena into consideration in his astronomical observations, and it must be said that he was a pioneer in this aspect, since few scientists took into consideration luminous and visual phenomena as he did in Greco-Classical Egypt.

His research on geography

Another of his most important works was "Geography", a text he completed since Marinus of Tyre (60 AD-130 AD) was unable to finish it.. It is a compendium of mathematical techniques to draw more accurate geographical maps, compiling different systems of projection and collection of coordinates of the main points of the known world at that time. Although his maps were a precedent for the elaboration of more precise maps, Ptolemy made the mistake of exaggerating the extension of Asia and Europe.

His maps are one of the oldest evidence of topographic charts with coordinates, longitude and latitude. Although they had important errors, it must be said that they were a great advance for the cartography of their time. His works served to perfect the methods of map projection and introduced the equivalent terms to what we know today as parallels and meridians, tracing the imaginary lines of altitudes and longitudes.

Use of simple language

Scholars of the figure of Claudius Ptolemy emphasize the simple language of the works that have survived the passage of time. Ptolemy was aware of the importance of keeping his message simple, understandable to all who read his works, whether they were educated men such as great mathematicians or simple people with a minimum of literacy..

Ptolemy wanted the knowledge he knew to reach many people, regardless of their mathematical training. It could be said that he was a forerunner and had a reasoning typical of cathedral thinking, wanting what he had discovered to transcend in time. He wanted what he knew at the time to be useful so that people in the future could discover more from what he had discovered.

He knew that the simpler his works were to understand, the more they would be translated and the more influence he would gain.. This is why it is said that, thanks to this, several centuries later the knowledge collected and formulated by Claudius Ptolemy would serve the Genoese explorer Christopher Columbus, especially those concerning the calculation of geographical distances and maps of very distant regions. Ptolemy believed that the Earth was a sphere, which is why Columbus thought it possible to go to India in a westerly direction.