2 Euro BU

Constantin Carathéodory was born in Berlin as the son of a Greek diplomatic family and grew up mainly in Brussels. He initially did not pursue an academic career, but studied engineering at the Belgian Military Academy. He subsequently worked for a time in Egypt, including in connection with the construction of the Aswan Dam (Assuan-Staudamm). Only afterwards did he turn fully to mathematics.

At the University of Göttingen (Universität Göttingen), Carathéodory studied under leading mathematicians of his time and received his doctorate under Hermann Minkowski. He later taught at several German universities, including in Bonn, Hannover, Breslau, Göttingen, Berlin and Munich. He spent a large part of his academic career in Munich.

His work focused primarily on the calculus of variations and real and complex analysis. In measure theory, he developed a method that allows the concept of measurability to be defined precisely. To this day, this forms part of the mathematical foundations of area, volume and probability calculations. Theorems named after him are also found in function theory and in the study of conformal mappings. He also contributed to the mathematical formulation of thermodynamics by placing the second law on an axiomatic foundation.

Carathéodory was also involved for a time in establishing a Greek university in Smyrna. Under Greek administration, the institution was intended to become a scientific centre in the eastern Mediterranean, but as a result of the Greco-Turkish War (Griechisch-Türkischer Krieg) and the events of 1922, it never began regular operations. Carathéodory subsequently returned to Germany.

The coin issue associates him with the Greek scientific heritage, although his life was strongly shaped by international influences. The milestone birthday provided the specific occasion to commemorate a researcher whose work continues to have an impact beyond Greece in several mathematical disciplines.