Cathedral of St Michael and St John a rare example of one of only four 19th century Cathedrals in NSW and is the second Cathedral to be built in the colony. The design of the building is one of only a few prepared by English architect Charles Hansom for use in Australia and notably modelled on St Osburg's Church in Coventry dating from the 1840s. The place is important in demonstrating the principal characteristics of a class of cultural or natural places/environments in New South Wales. The Cathedral of Saints Michael and John is representative example of a mid 19thbcentury Catholic Cathedral which was established during a
St Mary's Cathedral Church expensive. Mountfort seems to have ignored the perishable and limited qualities of wood, and built a vast church worthy of the finest stone. St Mary's covers an area of and has architectural features normally associated only with the great medieval cathedrals of Europe. Bishop William Cowie instigated the decision to make St Mary's the Cathedral Church during 1887, and the first part of the church, consisting of the Chancel and three bays of the Nave was consecrated and used from 1888. The church was completed to its present state by the addition of the four final bays and consecrated in