[citation needed] On 1 May 1850, the barque Clara arrived in Wellington Harbour from Auckland bringing the first bishop of the diocese, Philippe Joseph Viard, S.M.

Within three weeks of his arrival, accumulated funds collected by Catholics were placed in a special bank account at his disposal, and the site for the new cathedral was bought in Thorndon.

The bishop also chose as the site for his mission, two sections adjoining this, both in Hawkestone Street, now occupied by St Mary's College.

[1]: 146 On 8 September 1850, on "a lovely day, bright, calm," the feast of the birthday of Mary, Bishop Viard laid, "with a procession and all form", the foundation stone of the church which was to be his cathedral.

[1]: 146  The Cathedral of St Mary was complete enough to be blessed and opened for worship on Sunday 7 December 1851, the eve of the feast of the Immaculate Conception.

Some finishing work still remained to be done, but the Bishop wanted the context of the feast day, for the cathedral was being dedicated to Mary under that title.

But after the New Zealand Constitution Act 1852 was passed by the United Kingdom Parliament, the buildings of the Wellington Provincial Council were opened across Hill St from the cathedral.

After the Requiem Mass and a subsequent long funeral procession around the streets of Wellington as far as Te Aro, 1,500 people of all denominations crowded the cathedral for the burial.

[2]: 94  On 26 November 1874, Viard's successor, Francis Redwood, was received "solemnly and canonically" in the cathedral "then unfinished except in the chancel".

[2]: 173 At approximately 8:30 am on Monday 28 November 1898, the dry timber of the tower of the cathedral caught alight when a workman was burning off old paint.

[2]: 172–175  However, some eyewitnesses attested that when the cathedral tower fell, the statue hung momentarily in mid-air before descending slowly and gracefully and in an upright position to the ground, where it landed completely undamaged.

The parish church to replace St Mary's Cathedral in Thorndon, the Basilica of the Sacred Heart, was opened on 3 February 1901.

The Wellington Independent, in describing St Mary's Cathedral when its extensions were nearing completion in December 1867, stated that the original building opened in 1851 was lengthened by 10 metres (33 ft) and that the early English Gothic or decorated style had been adopted.

The whole of the building stood on the original brick foundation, and was built mainly of New Zealand timber, such as tōtara and rimu.

About one foot above the third floor of the tower were four double pointed arched openings, fitted with moveable louvres for the cathedral bells.

This had the inscription: "This statue was presented and blessed by the Right Reverend Philip Joseph Viard, Bishop of Wellington, on the eighth day of September, 1867.

From the top of the parapet rose the spire, crowned by a gilded wrought iron Latin cross, 1.8 metres (6 ft) in height.

The dado round the walls was 1.8 metres (6 ft) high of figured, varnished, red pine, gothic panels.

[5] John Stacpoole, an architectural historian, in discussing the many wooden ecclesiastical buildings designed by Christian Julius Toxward, has stated that "St Mary's was the most interesting, being quite different from any other interpretation of the Gothic style so far seen in New Zealand."

Great play was made with valances and gable crestings ... while even the undersides of the flying buttresses were deeply toothed.