In 1891, in the Supreme Court of New South Wales, Mrs. Olivia Mayne brought an action for breach of contract against two brothers, theatrical entrepreneurs, James and Charles MacMahon. Mrs. Mayne claimed the MacMahon brothers owed her money for the hire of her property, a boxing kangaroo called “Fighting Jack.” The MacMahons contested her claim, hoping to avoid their obligation by disputing the legally binding nature of the agreement they had made with her. The argument became one about the contractual capacity of a married woman.