ὅδε οἶκος, ὦ ἑταῖρε, μνημεῖον ἐστιν ζῴων τῶν σοφῶν ἀνδρῶν, καὶ τῶν ἔργων αὐτῶν

Mihailo Petrović was a great figure of Serbian science and culture. Having obtained the highest possible education in Belgrade, he continued his studies at the Ecole Normale Superieure in Paris where he got the following degrees: Licence es sciences mathematiques (1892), Licence es sciences physiques (1893) and Docteur es sciences mathematiques (1894). His Ph.D. thesis *Sur les zeros et les infinis des integrates des equations differentielles algebriques* was approved by Ch. Hermite, E. Picard and P. Painleve. From 1894 when he returned to the country until 1938 when he retired, Petrović was Professor of Pure Mathematics at the Philosophical Faculty in Belgrade.

Petrović published an impressive number of papers in important mathematical journals all over the world. He was chiefly interested in what is now called Classical Analysis, but what was at that time, called Modern Analysis. Roughly speaking, that is the analysis of the properties of various real or complex functions defined by power series, definite integrals or solutions of differential equations. Some of his results were recorded in mathematical literature of the time. For instance, the most important result from Petrović's Ph. D. thesis found its place in *Picard's classic Traite đAnalyse*, t.3, Paris 1896, pp. 356-359. Furthermore, many of his results served as a starting point for further research and were developed by other mathematicians.

Petrović attended various international congresses where he read his papers. He was a member of many Academies and Societies. Petrović was exceptionally effective as a teacher and an organizer: numerous generations of mathematicians graduated and obtained their Ph. D. degrees under his guidance. In 1894 he was the only professor of Pure Mathematics at the Faculty, but when he retired in 1938 the Department of Mathematics was popularly called *a beehive of research*. He was the founder of two mathematical journals in foreign languages.

Petrović was also engaged in many other activities. He worked for the Army on the questions of cryptography, he patented five inventions, he was a passionate traveller and he wrote several travel books, he played the violin in an amateur musical company. However, his chief preoccupation besides mathematics was fishing (his nickname Alas means Fisherman). Fishing was not only Petrović's hobby; he took the matter much more seriously. For example, he was delegated by the Ministery of Economy to conduct negotiations regarding fishing with neighbouring countries and he was also very active as a fishing legislator.

In 1941, at the age of 73, Petrović put on his Lt. Colonel's uniform, joined the Army, and spent several months in a German prisoner of war camp.

Contemporaries of Petrović often witnessed that he was an honest, honourable, and above all an extremely modest man.

Author: Kečkić, Jovan