The Prosopographic Database of German Engineers 1825–1970 contains a multitude of biographical information. Given a set of research interests by collaborating historians, this paper discusses the steps undertaken (1) to extract engineering subjects from unstructured text entries in the database accompanied with geospatial and temporal information, (2) to adapt existing visual representations to facilitate exploratory analyses, and (3) to design a visual interface to support the interactive composition of engineering branches from engineering subjects to enable the comparative analysis of geospatial-temporal developments in engineering. Usage scenarios outline the benefit of the proposed visualizations for modern prosopography research.