The Sisters of Mercy opened this school in 1882. It was a primary and secondary school for girls. And for many years there was also a boarding school for students who lived too far away to travel to school every day.

The secondary part of the school was called St Mary’s High School, and the primary part of the school was called St Ursula’s School.

The Sisters used rooms in their convent, All Saints Convent, as classrooms. The school became very popular, and so more classroom had to be built.

In 1949 all the primary school children at St Ursula’s School were transferred to St Patrick’s School, and so the Sisters were now only teaching secondary school girls at St Mary’s School.

By 1953, it was decided that St Mary’s School needed to be rebuilt as the classrooms were becoming very old. So the old St Mary’s classrooms were demolished and new classrooms were built. The school closed in 1973 when it merged with Marist High School (a boys school) to became John Paul II High School.