Mary Helen MacKillop RSJ was an Australian religious sister who has been declared a saint by the Catholic Church, as St Mary of the Cross. Of Scottish descent, she was born in Melbourne but is best known for her activities in South Australia. Together with Julian Tenison-Woods, she founded the Sisters of St Joseph of the Sacred Heart, a congregation of religious sisters that established a number of schools and welfare institutions throughout Australia and New Zealand, with an emphasis on education for the rural poor.