Albertus Magnus (c. 1200–1280) was a medieval naturalist and polymath in Regensburg, in what is today Germany, who aimed to fully understand the knowledge of his time and present it clearly in textbooks. He is said to have commented on all sources that provided new insights at the time (Greek and Roman classics recovered via the Islamic world, along with learned Arabic commentaries), including all the works of the philosopher Aristotle (384–322 BC).

Albertus Magnus wrote more than 70 books and essays by hand, which is said to probably fill more than 22,000 printed pages today. His writings included botany, astronomy, chemistry, physics, biology, and geography, and made original contributions to logic, psychology, metaphysics, meteorology, mineralogy, and zoology. He was a philosopher and theologian, interested in human beings, animals, plants, non-living matter, and natural phenomena. He later became a bishop and was called Doctor Universalis.

Albertus Magnus was the first German to hold a professorship in Paris at the most renowned university of the time. In Cologne, he led the newly founded Studium Generale, the first Dominican school in Germany. It is sometimes considered a forerunner of the later University of Cologne, one of the first universities in the German-speaking world.

De Mineralibus—On Minerals

His work on minerals, De Mineralibus (written around 1254 to 1257), is today regarded as a pioneering work in mineralogy. Albertus Magnus found not much on this subject and, therefore, had to develop it largely independently.

He listed and described gemstones, metals, and rock salts and explored the nature of stones, their formation, and composition. In doing so, he drew on Aristotle’s concept of the four elements—water, earth, fire, and air. As fundamental forces, these elements were regarded as the “building blocks” of nature and determined the properties of all things. For example, water and earth tend to move downward, while fire and air rise upward.

Based on this theory, which was widely accepted at the time, Albertus Magnus nevertheless argued rationally and cause-orientedly. He stated that the task of natural science is not simply to accept everything that is reported. Rather, they must investigate the causes of natural phenomena. “For it is [the task] of natural science not simply to accept what we are told but to inquire into the causes of natural things.” (De Mineralibus (Book II, Tractate ii, Ch. 1)).

He, for example, observed that rocks consist primarily of earth, the heaviest of all elements, which is why they sink in water. However, he noted that some stones, such as pumice, float on water. He explained this by suggesting that air was trapped within the pumice, making it float. When pumice is ground into fine sand, it sinks.

Albertus Magnus also conducted an optical experiment with a rock crystal, observing that when part of it was exposed to sunlight and another part remained in the shade, it projected a rainbow onto a wall. Drawing an analogy to the rainbow in the sky, he concluded that the water content within the crystal was responsible for this play of colors.

Books on Alchemy and Meteorology

Many of the works on alchemy that Albertus Magnus is said to have written were later attributed to him to make these works more important, such as the Libellus de alchemia (Little Book on Alchemy). Therefore, Albertus Magnus’ De Mineralibus probably contains the most work related to chemistry.

In his work on meteorology, Meteora, like Aristotle, Albertus Magnus defines meteorology broadly as the study of phenomena that originate in the upper atmosphere or are produced in the air. So Meteora includes discussions on comets, fire phenomena, wind, thunder, fog, clouds, and rain. Here, he explains, for example, the round shape of raindrops as a result of the heaviness of the element water.

In Padua, Italy, Albertus Magnus watched a man die while descending into a closed well to clean it. He attributed his death to toxic fumes inside the well.

In the field of geography, Albert Magnus described why he believed the Earth to be spherical and why he was convinced that people could live beyond the world known in the Middle Ages, that is, in the Southern Hemisphere of the Earth.

A Pioneer of Modern Science

Albertus Magnus placed great emphasis on experience and systematic, “objective” observation. “A great deal of time is required to ensure that all deception is excluded from an observation … It is not enough to make an observation in only one way. Rather, it must be repeated under different circumstances so that the true cause of the phenomenon can be determined with certainty”.

His rational interpretations of natural phenomena, his precise and systematic observations, and his experiments made Albertus Magnus a pioneer of modern science. The vast knowledge and versatility of Albertus Magnus, his broad scientific interest and immense curiosity about the world are still fascinating and remarkable today.

The Life of Albertus Magnus: Scholar, Bishop, Scientist

Albertus Magnus was born around 1200 in Lauingen on the Danube, now in Bavaria, Germany. In 1223, he studied the liberal arts in Padua, Italy, entered the Dominican Order, and then began studying theology, receiving his ordination in Cologne, now Germany.

From around 1228 to 1240, he served as a lector in various Dominican monasteries. Around 1240, he went to the University of Paris, France, where in 1245 he earned the title of Master of Theology and then taught for three years there. He intensely studied Aristotle and Jewish-Arabic philosophy. In 1248, he returned to Cologne, accompanied by his student Thomas Aquinas (c. 1225–1274), and led the newly founded Studium Generale, the first Dominican school in Germany, which is sometimes considered a forerunner of the later University of Cologne.

From 1254 to 1257, he was the Provincial of the German Dominican province, traveling extensively within and outside Germany. From 1260 to 1262, he served as Bishop of Regensburg, and from 1263 to 1264, he preached crusades throughout Germany and Bohemia. After 1264, he began teaching in Würzburg and Strasbourg. In 1269/1270, he finally returned to the Dominican Monastery of the Holy Cross in Cologne, where he died on November 15, 1280.

In 1931, Albertus Magnus was canonized and declared a Doctor of the Church (Kirchenlehrer), and in 1941, he was named the patron saint of natural scientists.