The school, which is one of the oldest existing schools in New Zealand, was founded in 1850 by Philippe Viard, first Bishop of Wellington and staffed from 1861 by a small group of religious sisters, the "Sisters of Mary", established by Viard.

Part of the land on which the school is situated was donated by Lord Petre, the 11th Baron Petre (1793–1850), who was a director of the New Zealand Company and whose family seat Thorndon Hall in Essex was an important centre of Catholic Recusancy from the time of Queen Elizabeth I.

Another part of the site was given by Sir George Grey, Governor of New Zealand out of public funds.

In 1861 the school was taken over by the Sisters of Mercy (absorbing the earlier group) when they arrived in Wellington in that year.

[4][5] As most other New Zealand Schools do, students in years 11–13 sit NCEA (National Certificate of Educational Achievement) examinations.