The Carlsberg Foundation is a veritable pioneering organisation, both nationally and internationally, when it comes to supporting Danish science. Niels Bohr has undoubtedly been Denmark’s foremost scientist in the period that the Carlsberg Foundation has existed. The relationship between the two giants was of mutual benefit and delight, contributing significantly to Danish and international physics for a whole lifetime. The Carlsberg Foundation was established in 1876 with capital of DKK 1 million provided by J.C. Jacobsen, founder of the Carlsberg Breweries. The purpose of the Foundation was to promote natural sciences, and it became a pioneering organisation both nationally and internationally. It was J.C. Jacobsen’s wish that the Foundation should be entrusted to the care of the Royal Danish Academy of Sciences and Letters, and that its board of five members should be elected from within the Academy. Today, the Carlsberg Foundation is still a key supporter of Danish science. The Four Fs (left to right: Christiansen, Høffding, Bohr and Thomsen) at an evening gathering in Bohr’s home. The drawing, by Des Asmussen, was a gift to Bohr from Christiansen’s daughter, Johanne Christiansen, on his 70th birthday in 1955. Niels Bohr, born in 1885, has undoubtedly been Denmark’s foremost scientist during the lifetime of the Carlsberg Foundation. So what was the relationship between the pioneering organisation and the eminent Danish scientist? As a son of the internationally acclaimed physiologist Christian Bohr, Niels Bohr was born into Copenhagen’s academic world. Niels Bohr himself said that, as children, he and his siblings were allowed to be present when their father and three other members of the Royal Danish Academy of Sciences and Letters met in the evening for intellectual discussion in the Bohr family home. The group became known as the Four Fs, comprising physiologist (Danish fysiolog) Christian Bohr, philosopher (filosof) Harald Høffding, physicist (fysiker) Christian Christiansen and philologist (filolog) Vilhelm Thomsen. When Niels Bohr began his physics studies at the University of Copenhagen, Høffding and Christiansen were the two tutors with whom he was most closely connected. As the only physics professor at the university, Christiansen also supervised Bohr’s master’s examination (1909) and his doctoral thesis, which he defended on 13 May 1911. It has often been observed that Bohr’s first application to the Carlsberg Foundation, dated 20 June 1911, for funding for an international study residency following the completion of his doctorate, is exceptionally brief. It clearly helped the positive assessment of Bohr’s qualifications that two of the Four Fs, Christiansen and Thomsen, were members of the Carlsberg Foundation’s board at the time. It should be noted, however, that all Bohr’s subsequent applications to the Carlsberg Foundation were especially detailed and conscientiously completed. Bohr’s first application to the Carlsberg Foundation was to fund an international study residency. Bohr’s international study residency in 1911 and 1912, first in Cambridge and then in Manchester under the supervision of the experimental physicist Ernest Rutherford, paved the way for his revolutionary model of the atom, which he published in 1913 upon his return to Copenhagen. In Copenhagen, Bohr worked from 1912 to 1914 as a research assistant, his salary supplemented by funding from the Carlsberg Foundation. In 1914, he returned to Manchester, taking up a post as senior lecturer, and remained there for two years until a professorship was specially established for him at the University of Copenhagen. As a professor, Bohr worked first under wretched conditions at the College of Advanced Technology (now the Technical University of Denmark), where the university rented rooms for physics research and teaching. In 1916, the young Dutch physicist Hendrik Anton Kramers came to Copenhagen on his own initiative to study with Bohr. In the following years, many young international physicists also made the trip, funded by the Carlsberg Foundation, to work under Bohr. “Bohr received funding from the Carlsberg Foundation every year from his appointment as professor in 1916. In addition to the funding for special projects and expansions, he also received a regular annual grant for assistance and apparatus.” Bohr worked hard for the establishment of an institute connected with the professorship. His ambition was realised in 1921, when the University of Copenhagen’s Institute of Theoretical Physics on Blegdamsvej was ready to move into. In his speech at the opening ceremony, Bohr stressed the importance of conducting experiments to back up theoretical work. Two years earlier, the Carlsberg Foundation had given Bohr what, at the time, was its highest ever grant to finance a grating spectrograph for experimental studies of atomic structure. Bohr had a strong attachment to Denmark, and the only one of many job offers from abroad that he seems to have seriously considered was a research position established by the Royal Society of London offering the prospect of working with Rutherford, who had now moved to Cambridge University. In the meantime, Christiansen and Jørgensen had been replaced on the Carlsberg Foundation’s board by the mathematician Johannes Hjelmslev and the physiologist Valdemar Henriques (who had succeeded Christian Bohr as professor in 1911). In order to prevent Bohr being lost to Denmark, on 3 September 1923 the two men wrote a long letter to the Foundation’s board proposing that the Carlsberg Foundation, in conjunction with the Danish government, should create a position for Bohr as a “free scientist”, whereby the Carlsberg Foundation would “win great honour by lending its considerable weight to enabling our country, in this matter of significant national importance, to rise up and rival a rich and powerful country’s efforts to increase and strengthen its scientific work by attracting to its flag the world’s best minds”. Once the Danish government had agreed that Bohr could be exempt from all teaching obligations, the Carlsberg Foundation granted a considerable permanent supplement to Bohr’s salary, after which he remained in Denmark for the rest of his life. In 1923, Bohr’s institute was the first to receive funding for an expansion from the International Education Board, which had just been established with funds from the Rockefeller Foundation to restore physics and other academic disciplines in post-war Europe. In connection with the expansion, the Carlsberg Foundation again granted another record sum for apparatus. Newspaper excerpt from the meeting of 11 December 1931, at which Bohr was offered the Honorary Residence. Bohr enjoys the view of the Honorary Residence’s garden, 1935. In his will, J.C. Jacobsen had stated that — following the death of his widow and son — his house should be turned into an Honorary Residence for life “for a deserving man or woman within the fields of science, literature or art.” The resident was to be chosen by the Royal Danish Academy of Sciences and Letters upon the recommendation of the Carlsberg Foundation, which was also responsible for ongoing expenses related to the residence. The first honorary resident, chosen in 1914, was Bohr’s tutor, Harald Høffding. When Høffding died in 1931, the Carlsberg Foundation recommended Bohr, who moved into the Honorary Residence with his family the year after. In the 30 years that Bohr lived there, the Honorary Residence at Carlsberg regularly served as a venue for official receptions in Denmark, only surpassed in that capacity by the Queen's palace, Amalienborg. After Hitler came to power in Germany, Bohr worked determinedly, with the assistance of the Carlsberg Foundation and others, to rescue young persecuted Jewish physicists from Nazi Germany. Around the same time, Bohr resolved to give over the theoretical and experimental research at the institute to nuclear physics and obtained funds for his same-aged colleague and close friend Georg von Hevesy, who had felt compelled to leave Germany, to help with the transition. Many years before, Hevesy had developed his radioactive indicator method, which made it possible to study, among other things, biological processes. However, it was not until 1934, when the physicist Enrico Fermi and his group in Rome were able to produce artificial radioactive isotopes, that the method could be implemented for real. In October 1934, this led to Bohr, Hevesy and the physiologist August Krogh drawing up a project for the Rockefeller Foundation, which was then limiting its support for projects in “experimental biology”. Shortly after the Rockefeller Foundation’s decision in April 1935 to grant funds for a five-year project, a highly placed representative of the Foundation wrote in his diary that Bohr “is so full of enthusiasm for the plans for physical-biological research that he is unable to talk about anything else. He says he expects that in three years he will be devoting all his time to this work”. This proved to be wishful thinking on the part of the Rockefeller Foundation. As the Foundation was aware, the apparatus that was the subject of the application — chiefly a cyclotron — could also be used for research in nuclear physics. When on 25 January 1935 Bohr applied to the Carlsberg Foundation for a high-energy laboratory, he stated as grounds for the application the transition to nuclear physics at the institute. He made no mention whatsoever of the biological project, even though he had presented the laboratory to the Rockefeller Foundation as a supplement to the biology project. At that time, Bohr was closer to the members of the Carlsberg Foundation’s board than ever before. Hjelmslev and Henriques were still members, and Bohr’s close friend and colleague, the chemist Niels Bjerrum, had joined in 1931. The board’s new chairman was another close friend of Bohr, the philologist Johannes Pedersen. Bohr’s application to the Carlsberg Foundation was hardly therefore tactically based and presumably reflected his real motivation. Niels Bohr, Niels Bjerrum and Johannes Pedersen at dinner in the Carlsberg Museum, 1958. The Carlsberg Foundation actively participated in the further development of nuclear physics at Bohr’s institute. In 1935, the Foundation contributed to a present for Bohr’s 50th birthday, namely 600 mg of radium for use both in nuclear physics and in Hevesy’s biological project. When Hevesy, who had collected the money for the gift, proudly reported on the matter to Rutherford, the latter replied: “The idea of celebrating people of a relatively young age is quite foreign in our country — only occasionally do we venture any form of appreciation of an individual, and in those cases we generally wait to see whether they can survive to 70, or even better 80! I believe, however, there might be something in the European idea of encouraging others!” The Niels Bohr Institute ca 1950 and 1965, by which time it had been expanded several times between its establishment in 1921 and Bohr’s death in 1962. In 1940 Bohr applied for, and obtained, a significant increase in the annual grant for scientific assistance and apparatus. Unlike the previous occasion that he had applied for an increase, in 1933, when he argued on the basis that mathematics in nuclear physics had become more sophisticated, Bohr now emphasised the theoretical and experimental work of nuclear physics. In the following years up to Bohr’s death in 1962, the Carlsberg Foundation continued to grant considerable funds to Bohr and his institute, not least for the then largest expansion of the institute at the start of the 1950s. Bohr actually received funding from the Carlsberg Foundation every year from his appointment as professor in 1916. In addition to the funding for special projects and expansions, he also received a regular annual grant for assistance and apparatus. Although Bohr was the longest serving president of the Royal Danish Academy of Sciences and Letters (1939-1962), he was never a member of the Carlsberg Foundation’s board. Nevertheless, he did enjoy close personal and scientific contact with its members. From the time of the grant for his studies in England in 1911 and 1912, it was the Carlsberg Foundation that he relied on when he needed extra funds. This was the case, for example, with the establishment of the institute in 1921, with the expansion of the institute in the mid-1920s, supported by the International Education Board, and with the transition to nuclear physics in the 1930s, started with funds from the Rockefeller Foundation. The Carlsberg Foundation was always the safe haven to which Bohr could turn to complete ongoing expansions and projects.