UNESCO ‘Memory of the World’Hamburg’s Red City Book in the Artefact Lab

21 May 2025

Photo: CSMC

It is an important piece of local Hamburg history: the Red City Book from the late 13th century is one of the key sources for understanding the city’s legal and commercial development in the Middle Ages. To gain insights into its history of production, it was brought to the Artefact Lab at the CSMC.

‘Hamburg is proud’, headlines the MOPO in June 2023: Three objects from the Hamburg State Archives had just been added to the UNESCO ‘Memory of the World’ register. One of them is the so-called ‘Rotes Stadtbuch Hamburg’, the ‘Red City Book Hamburg’. From around 1270, this codex in folio format, bound in striking red leather-covered wooden boards, was used to document Hamburg’s municipal law. In the age of the Hanseatic League, roughly until the 15th century, important decisions, legal matters, statutes, and trade treaties were recorded in it. As a central document of the administration, it helped to ensure order and a consistent jurisdiction in Hamburg over a long period of time.

Despite its significance, the content of the Red City Book was never made fully public. Only parts of the 14 chapters were accessible to the citizens of the city as an appendix to the ‘Ordeelbook’, the collection of court rulings and legal cases in Hamburg from the same period. The Red City Book never had the status of an official city law code.

Today, it is an indispensable source for understanding the city’s legal and commercial history in the Middle Ages. Because it was in use for so long, it reflects how legal and social conditions developed over time like almost no other document. However, a detailed material-scientific examination of the object, which is essential to answer important questions about its history of production and use, had never been conducted up to now.

To change this, the precious manuscript was brought to the CSMC, where it was investigated by a team of experts at the Artefact Lab for several weeks. After completing the analyses, they have now started evaluating the data. ‘The Red City Book is a particularly complex document because it passed through the hands of many users over a long period of time, who worked with it and edited it,’ says archaeometrist Olivier Bonnerot, who coordinated the project together with Claudia Colini and Grzegorz Nehring. ‘By analysing the material, we want to better understand the historical context of its creation’, he explains. ‘In particular, we are interested in how the materials and production processes used for the Red City Book relate to those of other manuscripts created in late medieval Germany and Western Europe. We hope that this work will provide deeper insights into the legal codification practices of the time.’

In the limited time available for the object to be examined in the lab, not nearly all the questions that would be worth investigating could be addressed. The researchers therefore decided to focus on a couple of selected aspects. One point of focus were the 21 illuminations contained in the Red City Book and, more precisely, the pigments comprising them. They want to find out whether the materials used to create them differ from the rest of the manuscript – and also whether there are differences between the individual illuminations themselves, which in turn could provide new insights into when and under what circumstances they were created.

To get closer to answering these questions, they examined the Red City Book is using various non-destructive analytical methods, including X-ray fluorescence and Raman spectroscopy. The former makes it possible to create maps of certain areas of the manuscript, yielding multi-layered information about the elements used in the pigments. The latter is a chemical analysis technique that provides detailed information about chemical structures using the interaction of a laser beam with the chemical bonds within the manuscript. In addition, imaging specialists Ivan Shevchuk and Kyle Ann Huskin, examined the entire manuscript together with literary scholar Marco Heiles to identify potentially important erased or illegible text. Combining the expertise of well-trained eyes and scholarly knowledge, they succeeded in recovering and interpreting previously illegible writing on two folios, which provides insights into the changes that were made in the Red City Book.

With their mobile equipment, the researchers of the Artefact Lab frequently travel to libraries and archives in Germany and abroad to study value manuscripts on site. Occasionally, however, precious objects are brought to Hamburg for examination, like in this case. Other recent examples are the Graz ‘Mummy Book’ or Islamic manuscripts from the famous library of Kairouan, Tunisia. With the analysis of the Red City Book in the lab, the potential of the Artefact Lab could now be harnessed to better understand an important part of the city’s own history.