I want to thank Karl-F. Rittershofer and Claudia Nickel for their support, proof reading, advice and the data they made available to me. Also thanks to the members of staff at the surveying department of the FH-Frankfurt, who provided me with the digitized and printed plans of the Dünsberg. Further thanks go to Susanne Sievers for proof reading and offprints of her articles, and Martin Girschick for general support and advice in Apple Macintosh related questions. Special thanks to Graeme Earl for his advice, suggestions and help whenever I had problems with the software or in writing my dissertation. Also thanks to the RGK, which provided me with a room in Frankfurt for two weeks and allowed me to use its excellent library. Last but not least I want to thank all my coursemates for their support and the good atmosphere on the course.