Yuriy Kotermak or  Yuriy Drohobych  (Latin: Magister Georgius Drohobich de Russia, Ukrainian: Юрій Дрогобич, Polish: Jerzy Drohobycz, Jerzy Kotermak Drusianus, Georgius Drohobicz, by birthname Yuriy Kotermak, Giorgio da Leopoli) (born 1450 in Drohobych – died February 4, 1494, in Kraków) was a Ruthenian philosopher, astronomer, writer, medical doctor, rector of the University of Bologna, professor of Kraków Academy, and the first publisher of a Church Slavonic printed text. He is the author of Iudicium Pronosticon Anni 1483 Currentis.[1]

Yuriy Kotermak was born in the city of Drohobych in Red Ruthenia, or Ruthenia Rubra (modern Western Ukraine), to a family of a salt maker Michael-Donat. He received his primary education in the local parochial school at St. George's Church. After that, he studied at a lyceum in Lviv (Polish: Lwów), or Leopolis, in Ukraine (then Palatinatus Russiae of the Kingdom of Poland). 

In 1468, Yuriy Kotermak entered the Jagiellonian University (Uniwersytet Jagielloński) in Krakow. Two years later he received his Bachelor's Degree and in 1473 his Master's. He taught during the summer months and participated in scientific discussions on Saturdays and Sundays. After he gained some significant achievements in Krakow, Drohobych travelled to Bologna University, where natural sciences and medicine were gaining popularity. There he improved his Latin, learned Greek, and continued his studies of natural philosophy. He paid particular attention to his studies in astronomy. It is worth noting that Kotermak's professor of astronomy was Girolamo Manfredi, one of the most renowned astronomers in 15th century Italy. Manfredi introduced his promising student to German astronomer Johannes Müller (Regiomontanus) who believed in heliocentrism; however, it had not been mathematically proven at that time.[2]:33

In 1478 Yuriy Kotermak received his Doctorate іn Philosophy, but continued his studies. This time he took up medicine. At that time natural philosophy disciplines were closely connected. Almost all philosophers of that time demonstrated equally strong prowess in astronomy and medicine, which allowed university professors transferring from one department to another. Similar methods were used in teaching both disciplines. It was done through reading and interpretation of Latin translations of Greek and Arab classical authors. Medicine was considered the key to understanding nature. Shortly after Kotermak completed his medical studies, he was offered a position to teach astronomy at Bologna University. At the beginning of 1481, the student body of the University elected Kotermak to become the rector of the school of Medicine and Free Arts.[2]:34 He was only thirty at the time. For a year, which was the regular term in office for an elected rector, he combined his academic responsibilities, which included teaching astronomy and medical research, with administrative obligations. He had civil and legal authority over the students and faculty who were under his supervision. In 1482 he received his PhD in medicine.



Yuriy Kotermak

In 1486, Kotermak returned to Krakow. He started his medical practice and taught medicine at Krakow University. Similar to his peers from Bologna, he based his lectures on the works of Hippocrates, Galenus, and Avicenna. A few years later, he received his professorship in medicine and became the doctor of the Polish king Casimir IV Jagiellon. In 1492, he became the Dean of the Department of Medicine. It was customary at that time for professors to have off-site meetings to discuss with students the issues that did not fit the official scientific doctrine. Copernicus attended Kotermak's meetings.[2]:35

It is worth noting that in the 15th century 'medicine' as we understand it today was viewed differently. There were two terms designated to define healing practices — the term ‘medicine' derived from the Latin verb medico, meaning "doctor". The practice of medicine, therefore, emphasized an ability to administer curative remedies.[3]:398 Such remedies might be the potions of quacks (quackery), developed only to make the seller a profit, or therapies that were invented or revised based on experiences of a particular practitioner with patients and remedies. What was crucial to good medical practice was what we call nowadays "clinical experience": an experienced judgment about what remedies would help a particular patient. Medical education in universities, therefore, might supplement but was not always necessary for "medical" practice. Hence, practitioners of medicine without university degrees were called "empirics" by educated physicians. For their part, physicians themselves practised another kind of healing art, "physic". The term derived from the Greek noun physis, meaning "nature". Physicians had to study natural philosophy because the purposes of physic were to preserve health and prolong life; healing the sick was an important part, but only one of the many parts, of physic. The physician had to be able to offer advice to the healthy as well as to the sick about how to live according to nature, to preserve health and prolong life. Thus "medicine" and "physic," as used in the late 15th century, are terms that suggest the differences between major traditions in the healing arts: one based upon experience, the other upon learning; one concerned primarily with healing, the other primarily with the preservation of health.[3]:399 Drohobych's appointment to King Casimir's court is an indication that he succeeded in both healing fields because such an important position required extraordinary knowledge of philosophy and natural philosophy as well as practical experience in curing illnesses.

His teaching at Bologna did not interfere with his experiments in astronomy. In a letter, which he sent in early 1478 to his friend Mykola Chepel in Poznań, Kotermak mentioned his calculations of planetary positions during a year. According to his observations and calculations, he estimated the exact time for two lunar eclipses; he also included a chart of the phases of the Moon for a year. In the letter, Drohobych described how he had calculated the geographic locations of major cities in what is now Poland and Ukraine. He also gave predictions concerning political events that had been taking place in Europe, Egypt, Turkey, Arabia, and India. Mykola Chepel shared these notes with his colleagues at Poznań University. The news about Drohobych's findings quickly spread among many learned people in Europe. One of the first German Humanists and book collector, Hartmann Schedel, copied these letters. In part thanks to his efforts, they were preserved for posterity.

Kotermak wrote a treatise about the solar eclipse that took place on July 29, 1478. He suggested that cosmic events of this nature may or may not have favourable effects on events on Earth, but they certainly would not cause catastrophes. In the early 1480s, Italy was at the forefront of book printing. Initially, all publications were religious; however, books about astronomy, botany, and geography had been growing in popularity, too. In 1483, Drohobych published in Rome his first book in Latin "Prognostic Estimation of the year 1483" (Iudicium Pronosticon Anni MCCCCLXXXIII Currentis).[2]:36 It was a nineteen-page publication of astrological (zodiac) calendars, which were popular at that time that helped its readers to make predictions about events on Earth depending on the planets' positions. This publication had several essential elements: Kotermak gave accurate predictions for two lunar eclipses; he provided accurate calculations of the phases of the Moon; he also touched upon the subject of planetary movement. Furthermore, he indicated that the geographic coordinates were an essential factor in determining the sun's and planets' positions. Depending on the geographic location of the observer, the positions of cosmic objects would vary. His longitude calculations were not error-free, however. He deserves credit for being the first Eastern European scholar who in a printed publication indicated the exact geographic coordinates of several Ukrainian, Polish, and Lithuanian cities.[2]:37

Weather forecasting was another aspect of Kotermak 's publication. He suggested that by observing atmospheric phenomena, one can predict the weather. He also argued that climatic conditions depended on the latitude of a geographic location. One of the most critical aspects of this treatise was the author's vision that the world is not an abstract notion and that humans are capable of learning its patterns and laws. In the foreword to the treatise, Kotermak wrote that even though our eyes cannot see the end of the boundless skies, our mind can. That we learn from the effect of the cause and from the latter, we truly learn.[4]

In 1491, Kotermak published one of the first books in Church Slavonic language "Осьмогласник", ("Octoechos "or "Antiphonal") and the first books in Ukrainian "Часословець" ("Horologion" or "Book of Hour"), "Тріодь пісна" and "Тріодь цвітна" (“Triodion”). All these publications built the foundation for the further development of the Ukrainian cultural identity.

Yuriy Kotermak (Drohobych) died on February 4, 1494, in Krakow, at only 44. However, he left behind a rich legacy. During his tenure on the faculty of Krakow University, humanistic ideas began to gain popularity among professors and students.[5] Kotermak was the first Ukrainian scholar who began to advance these ideas in Ukraine. As time went on, he found many followers among Ukrainian scholars and students who studied in Italy and Poland and who disseminated these ideas upon their return to their homeland. In the mid-15th century, due to the lack of internal and external stimuli, Ukraine's education system slipped into decay. Drohobych and his followers created a niche that helped to preserve, sustain, and develop socio-cultural and philosophical ideas that lay the foundation for Ukraine's revival by the 17th and 18th centuries. Their legacy played an essential role in preserving the national identity at a time when present-day Ukrainian lands belong to different rulers.


  1. Magistri Georgii Drohobich de Russia. "Iudicium Pronosticon Anni 1483 Currentis". Retrieved August 4, 2014.

  2. Українська педагогіка в персоналіях – ХІХ століття / За редакцією О.В. Сухомлинської / навчальний посібник для студентів вищих навчальних закладів, у двох книгах// «Либідь», - К., 2005, кн. 1., стор.

  3. David Lindberg, Reappraisals of the Scientific Revolution, Cambridge University Press 1990.

  4. Довідник з історії України. За ред. І.Підкови та Р.Шуста. — К.: Генеза, 1993

  5. Orest Subtelny, Ukraine: A History, University of Toronto Press 1988, p.155

  6. https://howlingpixel.com/i-en/Yuriy_Drohobych 

Yuriy Kotermak (Drohobych), 1494 year