Thank you Wolfgang. This works and it will very likely also work for my project.
I'm afrraid though that I left out an important detail, namely that the ToC itself must be mentioned in the ToC.
What I'm expected to emulate is the following: (with real pagenumbers of course)
CONTENTS
Acknowledgements i
Abstract ii
Contents iii
List of Illusttratiions iv
List of Tables v
Abbreviations and Library sigla vi
Preface vii
Chapter 1 8
Chapter 2 etc.
So my real question should have been: Is there a way to place the ToC in an unnumbered chapter, which should not be at the very beginning of the book?
But you have suggested the answer already: Changing \title{Contents} to \prechapter{Contents} does just that. Clean solution for an, imho, odd request.
Best regards,
Robert Blackstone