This lavishly illustrated thesis presents for the first time a comprehensive study addressing the Steelyard portraits of Hans Holbein the Younger within their cultural and historical context. From an analysis of Holbein's compositions and related documents, Petter-Wahnschaffe shows the iconographical development of merchant portraits and their purpose as part of a series.

The author commences by focusing on the portraits of Georg Gisze, the so-called Hans von Antwerpen, Dirck Tybis, Cyriacus Kale, and Derick Berck, which are considered as Steelyard portraits due to the identification of the sitters, which has been ascertained from iconographical detail in the portraits. The business letter, showing the address and trademark, and held by the sitter as authentic evidence of success, is considered to be a crucial link between the portraits. By exploring the paintings in detail, Petter-Wahnschaffe recognizes the potential audience within the circle of the Hanseatic League. She also observes a general attitude of temperantia, while the heading “Jesus” on a note of the Tybis-portrait is only acknowledged as a pious phrase. Petter-Wahnschaffe explains the conceptual difference of the Gisze portrait from the others in the series by stating that its larger scale and depiction of the lavishly furnished study in contrast to the simplicity of the other portraits was owing to the sitter's aspiration for an influential position in the Steelyard, the Hanseatic League's branch office in London.

By seeing only these five portraits as part of an oeuvre with narrowly defined characteristics, Petter-Wahnschaffe has chosen to exclude the portraits of Herman Wedigh and Derich Born, which have been hitherto accepted as Steelyard portraits by scholars. Apart from formal criteria, such as the absence of business letters, Petter-Wahnschaffe argues that no document proves the sitters’ Steelyard membership at the time of their portrayal. She also excludes on formal criteria a series of anonymous portraits attributed to Holbein, which have been ascribed to the Steelyard-oeuvre on account of their similar composition. Her research is enriched by carefully examining Holbein's other commissions from the Steelyard merchants, including designs for the triumphal procession for Anne Boleyn's coronation in 1533 and “The Triumph of Wealth and Poverty.” While the works reveal the merchants’ desire for prestige and the pursuit to promote their image, Petter-Wahnschaffe argues that as Holbein is entrusted with all these works they must belong to a common visual program. Even though a reconstruction of the former steelyard is no longer possible and none of Holbein's works are recorded in the inventories, the author claims their guildhall would have been a worthy place to exhibit the “Triumph” together with the portraits. She suggests further that the political situation in London, trade restrictions, and hostility resulted in a strong sense of community which led to a new way of representing the Hanseatic League in times of economic prosperity, which differed from that occurring in places such as Bruges and Antwerp where new buildings had been erected.

Adopting the suggestion of Arthur Bensley Chamberlain (Hans Holbein the Younger [1913]) that the portraits were designed as a series, Petter-Wahnschaffe also opposes the current academic opinion that the panels were produced for the merchants’ families, pointing to their official character and learned epigrams. Adapting Netherlandish merchant portraits, Holbein developed, according to Petter-Wahnschaffe, a new accepted type of professional portrait. The business letter as its crucial feature assures the viewer of the sitter's virtuousness and his membership of the Steelyard. Although Petter-Wahnschaffe explains the variable composition of the portraits as part of Holbein's creative talent, she does not take into account his gift for realistic and detailed depiction, which could have attracted new clients among the Hanseatic merchants. Moreover, it seems that only the institution itself was capable of establishing a systematic series and guaranteeing a lasting public display. Petter-Wahnschaffe acknowledges that the intention of the individual merchant must have been to take the expensive portrait to his home country after he completed his duties in London. The portrait of Joest Hesset painted by Ludger tom Rings, probably in the style of a Steelyard painting which was still located in London, is not necessarily proof of an existing series. The immense difference in size between the wall painting and the portraits and the fact that after 1536 Holbein probably received no further commissions, supposedly owing to financial problems, speaks against a planned series.

Nevertheless, by placing the Steelyard portraits in a wide historical context, Petter-Wahnschaffe offers the opportunity for a critical reassessment of the oeuvre. In addition, the thorough documentation in the appendix cataloguing all the discussed works by Holbein will provide an invaluable resource for future researchers.