Mary Mayne was the mother of Mary Emelia and James Mayne, two of the most significant benefactors to The University of Queensland, and the impulse for their philanthropy can partly be traced directly to her. She was an extremely successful businesswoman in colonial Brisbane, yet her business achievements have been overlooked by assumptions that the family's wealth came only from the foundations laid by her husband, Patrick — even though it was her fortune, as well as his, which funded her children's final bequests to the university. By the time of Patrick's death in August 1865, Mary was experienced in business, which was unusual for married women during this era. Her experience and skills enabled her to take over the administration of his estate and, despite his debts, to preserve most of his property holdings. At the same time, she amassed her own fortune. Although she faced a number of hurdles, her success proves that widows with skills and assets were able to operate as effectively as men in the commercial world, and undermines simplistic assumptions about the impact of gender discriminatory barriers in colonial society.