Mary Helen MacKillop RSJ, religious name Mary of the Cross, was an Australian religious sister of Scottish descent who has been declared a saint by the Catholic Church. 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.