This thesis is dedicated to my late mother, Bronwyn Myers. As a scientist, cellist and amazing mother and friend, she not only loved me fiercely and unconditionally, but encouraged me to explore and question the world and try to make sense of it.

I would like to thank a number of people who helped bring this thesis to life. Firstly, to my extremely knowledgeable, patient and forward-thinking supervisors, Anna Scott and Clive Brown. Anna, thank you for helping me think outside the box, formulate arguments, and encourage me to pursue the ever spontaneous, unique and exciting sound world of early recordings and their significant value to exploring 19th-century music in an historically-informed way. Clive, thank you for your wisdom, vast knowledge of 18th-and 19th-century string treatises, thorough questioning of my research goals and practices, and for your and Dorothea’s generous hospitality during my trips to Baden for our research meetings and artistic experimentation sessions.

Many thanks to Rachael Beesley, who introduced me to the fascinating world of historically-informed performance practices of 19th-century music with Ironwood in Melbourne in 2013. You have been a guiding force and kind, caring and encouraging violin teacher, colleague and friend ever since. I have gained so much expressive freedom through singing and improvising in my violin practice routine since then and I always learn so much just by playing next to you.

Thank you to Kati Debretzeni and Shunske Sato for teaching me historical violin during my studies at the Royal Conservatory of The Hague. I have gained technical, musical and expressive confidence from my lessons with these amazing musicians and teachers.

Thank you to the HIP players and researchers around the world who agreed to collaborate with me and explore the practical applications of portamento in current HIP singing and violin playing: Clive Brown, Rachael Beesley, Shunske Sato, Kati Debretzeni, Leila Schayegh, David Milsom, Emlyn Stam, David Greco, Koenraad Van Stade, Henriette Wirth, Sophie Wedell, Takuto Takagishi, Yotam Haran and Jesse Feves. And thank you to all the musicians around the world who continue to pursue innovative and exciting ways to reinvigorate 19th-century music, including, but not limited to, Neal Peres da Costa, Danny Yeadon, Erin Helyard, Robin Wilson, Skye McIntosh, Clare Holden, Jakob Lehmann, Jos van Immerseel and Kai Köpp.

Thank you to my Masters Circle leader, Bart van Oort, for always asking the difficult questions, encouraging us all to delve deeper into our research, and for keeping us all on track over the last year and a half.

Last but definitely not least, to my family and friends for showing undying love, patience and support through this journey. To my father, Dick Williams, not only for your steadfast love, but for continuing mum’s legacy of encouraging a scientific and inquisitive mind and for the hours of proof-reading, excel spreadsheet tweaking, and supportive chats across the globe. To my brother, Jack Williams, for giving me a speed crash-course in long-forgotten Year 10 maths, and for being the best brother a girl could ever ask for. And to Merrilee Mills, my (Fairy) Godmother, for your unconditional love, synonym knowledge, help with German translations, and movie nights to keep me sane.