Many of the late Mrs Theomin's friends shared their memories at the commemorative afternoon tea organised by the Southern Heritage Trust and Friends of Olveston.
"She was very keen on mountaineering, which was quite unusual for a woman in those days," Dawn Ibbotson (96) recalled.
"She used to climb Franz Josef."
Mrs Theomin was also recalled as a keen photographer, traveller, singer and philanthropist.
"Dorothy loved parties. She was very sociable," Mrs Ibbotson said.
"We used to go horse-riding together up Northeast Valley in the 1920s," childhood friend Daphne Jones (90) said.
The group of 60 included author Margery Blackman, who wrote the 2007 biography on Mrs Theomin, Dorothy Theomin of Olveston and long-serving Hallenstein Glasson Holdings chairman and Theomin family friend Ted Friedlander OBE (89).
Mrs Theomin (1888-1966) bequeathed the stately Edwardian house and its contents to Dunedin in 1966. It was opened to the public in 1967 and now attracts between 30,000 and 40,000 visitors each year.
Southern Heritage Trust founding trustee Ann Barsby said the Theomin family had been generous benefactors to Dunedin.
"We do about five afternoon teas here a year and they usually have a heritage flavour.
"We thought it would be to our mutual benefit to have one with the Friends of Olveston. It's such an important part of our history."
