On the facade of the National Museum in Prague, there are names of people who have contributed to the history of the Czech Republic. There are philosophers, astronomers, and mathematicians. One of those people – one of the first members of the Scientific Society – is Jan Tesanek. 

Mathematics always have been the subject of many studies; pan Tesanek did not pass by the agiotage around it in his time. Born in 1728 in Brandis nad Labem, he graduated from the Faculty of Arts in Prague. Growing up, he was fond of Aristotle’s philosophy and received a degree in philosophy; in the 1740s he joined the Jesuit Order, but under the influence of Joseph Stepling (Czech-German Jesuit priest, physicist, astronomer, mathematician, and meteorologist), he became acquainted with differential, integral calculus, and Newtonian physics. After ordination to the priesthood, he became a professor of Physics at the University of Prague. He lectured Mathematics and Physics with enthusiasm and modified the exposition according to the latest French and German knowledge. Thanks to him, regular special lectures on Higher Mathematics were introduced at the University. This was a novelty, but, unfortunately, few students were willing to join, and the content of lectures rarely changed. Perhaps it is because of the disinterest of students that later he lost his interest in continuing to raise the level of his lessons. 

In addition to teaching, pan Tesanek continued to work in the scientific research field; moreover, after the death of his teacher Joseph Stepling, he was appointed to the position of Director of Research of Mathematiсs and Physics in Prague. In his studies, he developed formulas for solving tasks in Astronomy and Physics. In his works in Mathematics, he explained the concept of the limit, referring to the works of such scientists as Euler and Dalembert. That was then used by him to define the basic concepts of differential and integral calculus. 

In his works on Physics, he did not conduct any experiments since he considered it unworthy neither of a real scientist nor a philosopher. Instead, he was mainly engaged in Theoretical Physics, which he raised to an unprecedented level of teaching at the University of Prague as a professor. He also addressed some selected problems from Newton’s Principles but was most interested in the principles of movement. He began publishing his commentaries and interpretations of Newton’s Principles in the mid-60s and continued to study Newton’s main work until his death. In Astronomy, he was mainly engaged in calculations of planetary orbits and had many works published about that particular topic as well.

During his life, Jan Tesanek managed to make a huge contribution to the study of Mathematics, Physics, and Astronomy. In the last years of his life, one of his students, well-known mathematician Frantishek Gerstner, took care of him. Jan Tesanek died in 1788 in Prague, “Magni Newtoni Commentator” is engraved on his gravestone, meaning “Commentator of The Great Newton”.