St Mary Helen MacKillop (15 January 1842 – 8 August 1909), also known as Saint Mary of the Cross, was an Australian Catholic nun who, together with Father Julian Tenison Woods, founded the Sisters of St Joseph of the Sacred Heart and a number of schools and welfare institutions throughout Australia. These schools and institutions had an emphasis on education for the poor, particularly in country areas.
On 17 July 2008, Pope Benedict XVI prayed at her tomb during his visit to Sydney, New South Wales for World Youth Day 2008. On 19 December 2009, Pope Benedict XVI approved the Roman Catholic Church's recognition of a second miracle attributed to her intercession. She was canonised on 17 October 2010 during a public ceremony in St Peter's Square at the Vatican. She is the only Australian to be recognised by the Roman Catholic Church as a saint.