After graduating as a historian in 1894, Bang decided to study the 700 registers in the Danish National Archives that record the Sound Tolls collected between 1497 and 1857. The Sound Tolls were one of Denmark’s main sources of revenue and were collected from all ships passing through the strait between Denmark and Sweden.

The ledgers provided unique insight into shipping and cargo, and Bang set out to organise the many numbers and details into a table format to make the records more accessible to historical researchers. 

It was a huge project, with data on index cards, manual records and the systematic processing of huge registers. Bang developed methods for extracting and comparing records about shipping and cargo over long periods. Her work resulted in two extensive volumes of tables, published many years apart.

This might have been the end of the story were it not for a critical review in 1925. By then, Bang had become a public figure though not as a historian with expertise in tolls and tables. Since 1924, she had been the Danish Minister of Education. Not only that, she was the first woman in the world to serve as a minister in a parliamentary government. 

The review was printed in Historisk Tidsskrift (Journal of History). The critic was the young historian Astrid Friis (1893–1966), later Denmark’s first woman to be appointed Professor of History (although she did not achieve her ambition of becoming the first Danish woman to be accepted into the Royal Danish Academy of Sciences and Letters). She launched a sharp attack on Bang’s academic method and findings. The review blew up in the press, and Bang came under fire. While the historians addressed the academic aspects, politicians and the press dug into Bang’s alleged conflicts of interest.

Friis accused Bang of cherry-picking source material and of flawed conclusions. She called it ‘a violation of statistical source material from the past’. The press pointed out that she had received funds from the state and the Carlsberg Foundation for more than three decades while her main occupations had been journalism and politics. Thus, as one paper put it, she had merely ‘browsed […] the old ledgers’; in fact, her engagement had been so sporadic that Volume 2 was released with ‘stupendous delay’ (Volume 1 in 1906 and Volume 2 in 1922).

Bang dismissed the debate with a shrug and stated that Friis’s purpose was simply to push her aside and take over the project for herself. While this may have been true, it did not improve Bang’s popularity among historians.

Eventually, the chairman of the Carlsberg Foundation, the historian Kristian Erslev (1852–1930), entered the discussion. He acknowledged that the publication of Bang’s material was delayed but pointed out that this is also the case for other major research projects supported by the foundation. He gave Bang’s work his full-throated endorsement.

The polemic died down, as polemics always do, and, besides, Bang was no longer receiving grants from the state or the foundation. After completing her tenure as minister, in 1926, she struggled with health issues, which weakened her and led to her death a few years later. 

The study of the Sound Toll registers continued, however. After Bang’s death, the political economist Knud Korst (1894–1962) completed the project in collaboration with other researchers, ultimately publishing five additional volumes of tables documenting shipping and trade through the Sound.

Today Bang’s and Korst’s work gives an insight into how researchers used to handle large data sets without the use of computers. The project was also an early example of international collaboration on historical data in the social sciences. From 2007 to 2020, the material was digitised and processed in the Dutch project 'Sound Toll Registers Online', which is now freely available on the internet. The funds awarded to the ‘grant glutton’ Bang were well spent, as the material is now one of the most famous sources of international trade history.

The chapter is written by Dorthe Chakravarty.