[1] The first St Paul's building was in Emily Place, just off Princes Street, where a plaque still marks the site of the beginning of the Christian church in Auckland.

[2] St Paul's was the seat of the Bishop of New Zealand, the Right Reverend George Selwyn, for his entire 28-year tenure and served as Auckland's cathedral for over 40 years.

Old St Mary's stood on the site of the present cathedral, but proved to be too small, badly ventilated and uncomfortable.

The diocese covers the area stretching from North Cape south to the Waikato River, across the Hauraki Plains and including the Coromandel Peninsula.

In those early days the then colony was regarded as one huge diocese which, including large areas of the South Pacific, covered almost one sixth of the Earth's surface.

Following the adoption of the Constitution of the Church of the Province of New Zealand, which was signed in St Stephen's Chapel, Judges Bay, Auckland, on 13 June 1857,[7] other dioceses were soon established: Nelson and Waiapu in 1858, and Wellington in 1859.

Following the creation of the dioceses Selwyn became ipso facto the Bishop of Auckland (though never formally styled as such), while retaining the primacy and continuing as the metropolitan.

In diaries kept by his contemporary, Attorney-General William Swainson, Auckland was at that time expected to be the permanent seat of the Metropolitan of New Zealand.

[9] The nave of the new cathedral dedicated to "The Holy Trinity" was designed by Professor Richard Toy, a New Zealand architect.

He combined two very different architectural styles, incorporating the existing brick & reinforced concrete neo-Gothic chancel, with the new nave, a contemporary design which has large areas of glass and a timber ceiling.

Glass doors the length of two sides light the vast space and accentuate the seemingly unsupported roof with its absence of visible structural support.

This surreal effect is made possible by a ridge and furrow roof system, a refinement of that first invented by the architect Joseph Paxton for his Crystal Palace in 1852.

The vast uncluttered space and fine acoustics realised by this ingenious construction allow multi-purpose use of the nave, including concerts and other performances.

A set of five stained glass windows designed by prominent English artist John Baker fit perfectly into the chapel.