Napoleon Bonaparte had jailed Pius VI who died in jail. When Pope Pius VII was elected he too was jailed by Bonaparte, who kept him prisoner at Fontainbleau.
The Holy Father vowed to God that if he were restored to the Roman See, he would institute a special feast in honour of Mary.
The military eventually forced Bonaparte to release the Pope and on 24 May 1814, Pius VII returned in triumph to Rome.
Twelve months later the Pope decreed that the feast of Our Lady Help of Christians be kept on 24 May.
The infant church in Australia had a special reason for turning to Our Lady . No priests were sent to the colony in its early days and Mass was not allowed except for one brief year until 1820. It was largely the Rosary in those early days that kept the faith alive.
Catholic Australia remained faithful to Our Lady and was the first nation to choose her under the title Help of Christians, as principal Patroness.
St Mary's Cathedral was dedicated in her honour by the Irish pioneer priest, Fr John Therry, who arrived in Sydney in 1820 and assumed responsibility for the planning and initial construction of the Cathedral.
When Australia became the first country to have Our Lady Help of Christians as Patroness, it became the first country to have a mother-cathedral under the same title.
The altar at St. Mary's, with its statue of Mary Help of Christians, was erected as a memorial to Fr. Therry's name.
The statue of Our Lady, Help of Christians, stands in the Chapel of the Sacred Heart in the Cathedral.
The Church has traditionally focussed on two aspects of Our Lady's help on this feast day.
Firstly, upon the role of Our Lady's intercession in the fight against sin the life of a Catholic.
Secondly, Our Lady is one who assists Christians as a community, through her intercession, in fighting against anti-Christian forces.
In the Opening Prayer for Our Lady Help of Christians, the Church prays that through Our Lady's intercession God will "grant wisdom to our leaders and integrity to our citizens", so that "under her protection Australia may be granted harmony, justice and peace".
Our Lady Help of Christians patroness of Australia and of the Military Ordinariate
Almighty God, deepen in our hearts
our love of Our Lady Help of Christians.
Through her prayers and under her protection,
may the light of Christ shine over our land.
May Australia be granted harmony, justice and peace.
Grant wisdom to our leaders and integrity to our citizens.
Bless especially the men and women
of the Australian Defence Force and their families.
We ask this through Christ Our Lord. Amen.
Our Lady Help of Christians, pray for us.