In the 1820s the richness of the black soil plains of the Southern Tablelands drew white settlers for agriculture and grazing and by the 1830s there was great pastoral expansion based upon the export value of Australian wool.

The foundation stone for the construction of a cathedral nave which was connected to the old church was laid on 12 December 1871 by Bishop Lanigan.

The materials and traditional Gothic design reflected his personal knowledge of European architecture, his skills and his influence.

[1] The transfer of the diocesan centre to Canberra in 1969 resulted in Saints Peter and Paul's becoming a parish church and no longer a cathedral.

Tracery of all windows, jambs, arches, turrets and crosses are of "Piedmont" stone from Sydney and are generally in good condition, indicating the durability of the material.

The walls are constructed from green porphyry, a particularly hard igneous rock that has been squared and brought to courses of 300 millimetres (12 in) in height.

The CMP notes that the greenstone, diorite porphyrite, is from a quarry on the Bungonia Road and is only found in very limited quantities and in one place near Goulburn.

Documentation indicates that there was a finial on every point, that each was different and that many are now missing, including to the top of the pinnacles on the four corners of the tower.

The walls of the nave and aisles are also cream with some gold leaf detail to window architraves and picture rails.

The fill is believed to have acted as a conduit, enabling moisture to rise into the sanctuary floor and some of the surrounding sandstone.

Recent excavation under the sanctuary is understood to have significantly reduced the damp although there remains some evidence of active groundwater.

[1] A survey in 1985 found: some settlement of footings to the south-west side, serious fretting and deterioration to the Verner Street steps and adjacent foundation walls, high moisture levels in ground and footings, some movement of the tower, fretting of mortar, movement of walls, cracking and possible roof spreading, lifting of sandstone copings, breakdown of flashing and poor roof plumbing.

The former Saints Peter and Paul's Cathedral provides physical evidence of Goulburn as a major ecclesiastical centre in the latter half of the 19th century.

Externally the Gothic architectural form is skilfully expressed in green porphyrite stone walls and sandstone detailing in combination with the dark purple slate roof.

[1] Saints Peter and Paul's is distinctive within the city, has exceptional streetscape value and makes a very important contribution to Goulburn's impressive collection of 19th and 20th century architecture.

[1] The use of locally quarried green porphyrite is technically of interest as a rare use of this material in such a quantity and in the quality of workmanship.

[1] St Peter and Paul's Former Cathedral was listed on the New South Wales State Heritage Register on 20 April 2009 having satisfied the following criteria.

The former Saints Peter and Paul's Cathedral is historically significant for the important role it played in the growth and consolidation of Catholicism in southern New South Wales.

As the growing congregation undertook an ambitious building program in subsequent decades with the erection of schools, orphanages, convents, hospitals and the presbytery, the cathedral played an essential role as its focal point.

[1] Its construction was largely due to Bishop Lanigan who served the Catholic community for many years and is buried beneath the sanctuary.

As well as designing the building he project managed construction of the nave and personally carved some of the fine stonework tracery.

[1] The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.

[1] Saints Peter and Paul's is distinctive within the city, has exceptional streetscape value and makes a very important contribution to Goulburn's impressive collection of 19th and 20th century architecture.

Its corner location, opposite the School of Music and within the sight lines of the Anglican Cathedral Church of St Saviour all serve to reinforce the landmark significance of the building.

For the large Catholic community in Goulburn and the wider Diocese it has been the focus for many of their important religious ceremonies and has benefited from gifts and dedications, including the donation of the Hill and Sons organ by Mrs Dalgleish.

[1] The place has potential to yield information that will contribute to an understanding of the cultural or natural history of New South Wales.

[1] The place possesses uncommon, rare or endangered aspects of the cultural or natural history of New South Wales.