Konstantinos Carathéodory was born on Saturday, September 13, 1873, in Berlin, into a family with deep roots in the scholarly tradition of the Greek communities of the Ottoman Empire. His father, Stephanos, was a diplomat and trusted ambassador of the Sublime Porte, a jurist from Constantinople, while his mother, Despina Petrokokkinou from Chios, also came from a distinguished family. The family’s origins extended to Bosnochori, Vyssa in Western Thrace, a place that embodied the memory of ancestral land and tradition.
The house in which he grew up contained an exceptionally rich library, filled with classical texts and works by major European authors: Plato, Aristotle, Goethe, and many others. The constant presence of books shaped his intellectual development from an early age and nurtured his love of study and knowledge. The entire family was highly educated: his great-grandfather was a physician and mathematician who had founded the imperial medical school of Constantinople, where he taught for forty years, while other relatives served as lawyers, ambassadors, and rulers. His cousin was the well-known writer Penelope Delta.
A love of learning
From a very young age, Konstantinos lived in a multinational environment. Although he was born in Berlin, the family moved to Brussels when he was about two years old. At home they spoke mainly Greek, but also Flemish, German, and Turkish. Their salon was frequently visited by important figures from politics and intellectual life, members of the broader aristocracy of the time, and young Konstantinos came into direct contact with European culture. His mother died when he was six years old—a loss that marked him deeply—but the family atmosphere remained oriented toward education and intellectual cultivation.
From 1883 to 1885 he attended schools on the Riviera and in San Remo, and later he enrolled in secondary school in Brussels. There, at a young age, he felt a unique attraction to mathematics, especially geometry. He realized that he had found his true purpose in life. His aptitude soon manifested itself in distinctions: for two consecutive years he took first place in Belgium’s national mathematics competition, confirming his exceptional abilities.
Contact with Greece
In 1891 he entered a military academy, where he received military and technical training, and then studied civil engineering at the Military School of Belgium in Brussels. He graduated in 1895 and began working as an engineer on various projects. He visited Chania, where his uncle Alexandros Carathéodory, governor-general of Crete, lived, and there he met Eleftherios Venizelos, with whom he maintained close ties. He later worked on Lesbos on public works projects, and in 1898 he went to Egypt to work on the construction of the Aswan Dam, one of the largest engineering projects of the time.
During his stay in Egypt, he studied the main entrance of the Pyramid of Cheops as well as ancient mathematical treatises, which rekindled his deep attraction to mathematics. At the same time, he published a related study, demonstrating that his heart now belonged entirely to mathematics rather than applied engineering.
Devotion to mathematics
Thus, in 1900, at the age of 27, he made a bold decision that surprised his family and friends: he abandoned the profession of engineer and returned to Berlin to study mathematics. His family, as well as close friends such as Dimitrios Vikelas and Markos Dragoumis, considered it reckless and almost comical to leave a secure position with promising prospects. He himself was not entirely certain that this new path would bear fruit, but he felt that only an unhindered engagement with mathematics could give real meaning to his life.
In Berlin he attended courses for two years under distinguished mathematicians such as Hermann Schwarz, Georg Frobenius, Erhard Schmidt, and Lazarus Fuchs. At Schmidt’s urging, in 1902 he enrolled at the University of Göttingen, then the most important center for mathematics, where he completed his doctoral dissertation entitled “On Discontinuous Solutions in the Calculus of Variations.” His supervisor, the renowned Hermann Minkowski, described the dissertation as one of the best ever submitted. In 1904 he was awarded his doctorate, effectively launching his brilliant academic career.
Modesty and rejection
At Göttingen he worked alongside great mathematicians such as David Hilbert and Felix Klein. Klein, even before the dissertation was examined, suggested that he prepare a habilitation thesis, and upon Hilbert’s recommendation he was granted the right to teach ahead of the usual schedule. In 1905 he qualified as a lecturer in mathematics at Göttingen, where he taught until 1908. His students affectionately called him “Cara” and spoke with admiration of his strict yet understanding and courteous demeanor.
Absolute silence and concentration prevailed in his lectures. Carathéodory, deeply modest, would refer to his own theorems by saying: “According to the theorem which I have the honor to bear my name…”. He was always willing to answer questions and encourage critical remarks from his students, whom he treated with respect as future colleagues.
Despite his success in Germany, Carathéodory never stopped thinking about Greece. He repeatedly sought a position at a Greek university, but the authorities did not show the proper appreciation. As he later recounted, the only possibility offered to him was that of being appointed as a schoolteacher in provincial schools. Thus, he was forced to continue his career in Germany. From 1913 to 1918 he held the chair of mathematics at the University of Göttingen, further enhancing his prestige.
The unfulfilled dream
In 1920, after the end of World War I and within the framework of the Greek presence in Smyrna, Eleftherios Venizelos invited Carathéodory to undertake the organization of the Ionian University. The great mathematician saw in this invitation a historic opportunity to serve the Hellenism of Asia Minor and to create a higher education institution that would become a “light from the East” for the entire region. With zeal and dedication, he worked on establishing and equipping the university, transporting books, instruments, and laboratory equipment from Germany.
His family settled in Smyrna, in a house in the Bouza district. His daughter enrolled in a Greek school to perfect her language skills. The love and respect shown by the city’s residents toward Carathéodory and his wife testified to the esteem he already enjoyed. However, this dream soon collapsed. In August 1922, the Greek front disintegrated, Turkish forces entered Smyrna, and the city was engulfed in flames. Carathéodory, at great personal risk, remained at the university until the last moment, trying to save as much as possible from the library and equipment. He ultimately managed to transfer a large portion to the University of Athens, while he himself escaped capture at the very last moment.
After the Asia Minor Catastrophe, he made new efforts to work in Greece. For a short period he taught at the University of Athens, where he encountered ingratitude, lack of understanding, and even hostility from some colleagues and students. Nevertheless, in 1930 Venizelos appointed him government commissioner for the organization of the Universities of Athens and Thessaloniki. He carried out this mission with enthusiasm and without financial gain, but shortly afterward he was informed by a formal letter that he was dismissed from his duties—an event that deeply hurt him.
Return and Nazism
Already from 1924, Carathéodory had settled in Munich, in the peaceful district of Bogenhausen, at 8 Rauchstrasse, with his wife and their two children. He grew particularly fond of the city, as it offered him the respect and recognition he had been denied in his homeland. He was appointed professor at the Mathematical Institute of Ludwig Maximilian University (LMU) and became a naturalized Bavarian citizen. Together with his colleagues Oskar Perron and Heinrich Tietze, he formed the renowned “triumvirate of Munich mathematicians.” In 1925 he became a full member of the Bavarian Academy of Sciences, and in 1928 he traveled to the United States, where he lectured at prominent universities and received an enthusiastic reception.
In Munich, Carathéodory lived a calm yet highly productive life. He used to walk daily in the “English Garden,” a vast green space near his home. There, strolling with his wife, his daughter, or his close friend and student Dimitrios Kappos, he reflected on mathematical problems and mentally organized the material for his lectures. He preferred to walk to the university, using the time to think and engage in an inner dialogue with himself.
The period of National Socialism was difficult. Carathéodory watched with pain the marginalization, persecution, and extermination of many of his Jewish friends and colleagues. He rejected Nazism and resisted attempts to “Nazify” science. Although the regime initially allowed him to participate in international conferences, in 1943 he was banned from traveling abroad, as he was considered to maintain “pro-Jewish” connections.
Religion and science
Alongside his scientific work, Carathéodory was deeply religious. Every Sunday he attended services at the Orthodox Church of the Transfiguration of the Savior in central Munich. During World War II, he even served as a trustee of the Greek Orthodox community, holding the keys to the church and protecting it from attempts by other Orthodox groups to appropriate it. He firmly believed that the church, dedicated by King Ludwig to the Greeks, should remain in Greek hands.
Konstantinos Carathéodory was not only a leading mathematician but also a person of wide intellectual interests. He attended theater and opera, visited exhibitions, and had a deep love for literature and philosophy. His personal library, which occupied a large part of his study on Rauchstrasse, included not only specialized mathematical works but also the writings of classical Greek authors such as Plato and Aristotle, as well as the complete works of Kant and Goethe.
“He soared into the heavens”
The circle of his life closed in Munich, the city he considered his second homeland. He died on February 2, 1950, at the age of 77. The rector of the University of Munich announced his death to the rector of the University of Athens with the words: “The spirit of the renowned Greek mathematician Konstantinos Carathéodory has soared into the heavens.” He was buried in the Waldfriedhof cemetery in Munich, alongside his wife. Today, his tombstone stands in the courtyard of the Orthodox Church of All Saints in Munich, while since 2018 the Greek Lyceum of Munich has had the honor of bearing his name.
