Theresa Walker and her sister Martha Berkeley were the first European-trained women artists in South Australia. They were professional artists who worked in several mediums and were particularly skilled in miniature portraiture – Martha executed painted portraits whereas older sister Theresa sculpted relief images in wax, an easily-worked medium for portraiture which had been popular in Britain since the late 1700s. During their careers, both sisters exhibited at the prestigious Royal Academy in London. They arrived in South Australia from England in February 1837, just six weeks after the colony was proclaimed, and their work here included historically significant early scenes of the settlement of Adelaide as well as commissioned portraits of many of the first colonists.
Among Theresa Walker’s best-known works from this time are her delicate wax portraits in profile of a Kaurna Aboriginal man and woman, whose names she recorded as Kertamaroo and Mocatta. Kertamaroo was also known as Murlawirrapurka and, to Europeans, as ‘King John’. Several copies exist of these paired medallions, as Walker was able to make moulds from her originals to produce multiple copies for sale. One pair was exhibited at the Royal Academy in 1841; another was given in 1840 to the wife of the colonial governor George Gawler, who had appointed Murlawirrapurka as an honorary police constable. Murlawirrapurka also assisted German missionaries as they compiled a 2000-word vocabulary of the Kaurna language. A significant intermediary between Kaurna and Europeans, he is depicted in European attire, whereas Mocatta is seen in traditional Kaurna clothing. Walker’s elegant portraits present a sympathetic and nuanced image of Aboriginal people from this period of early colonial contact.