Now chair of Sotheby's Australia, Geoffrey Andrew Smith was a university student when he met art dealer Robert Gould in 1990.
Smith, 42, is suing his former domestic partner, whom he separated from in 2004, for part of the art collection they amassed together. The collection contains works by Andy Warhol and Australian modern artists Sidney Nolan and Arthur Boyd.
Gould, 56, says the collection belonged to his gallery, Gould Galleries, and was not a private collection owned by them both.
The lawyer representing Smith, Richard Kendall QC, told the court in Melbourne his client was responsible for the success of Gould Galleries. Kendall said that Gould had experience in running a commercial gallery, but 'did not have a formal training in art', as reported by Nine News.
Kendall said that Smith had persuaded Gould to purchase an artwork for $50,000 (Australian dollars $51,500, €39,000) which sold two months later for $120,000 (Australian dollars $123,700, €94,000).
The trial continues.