Mary was Rev Johann Stähle's second wife. They met when she was the school teacher at Coranderrk Aboriginal reserve and moved with her husband to Lake Condah in 1875. The Board for the Protection of Aborigines (BPA) and the churches that ran missions preferred husbands and wives to manage and be matron of reserves. Mary's role was to train the females on the reserve domestic chores and skills, preparing young women for service and reinforcing gendered expectations amongst the reserve population and ideas of 'civilising' and assimilation. Historian Regina Ganter noted that whilst Mary and Johann may have been called Mama and Papa by the residents at Lake Condah, Johann was a strict disciplinarian and in 1880 Mary wrote to the BPA about an incident where a resident pulled a gun on her husband. This was around the period when a number of Aboriginal residents of Lake Condah wrote to the BPA complaining of their treatment by Stahle.