|Dom William Bernard Ullathorne OSB|
Arrived in Australia as Vicar-General
Soon, however, it was deemed desirable that the colony have its own bishop and so the Vicariate Apostolic of New Holland was established in 1834. It encompassed the entire continent of Australia (including Tasmania). Dom John Bede Polding OSB of Downside Abbey, England, was appointed as the Vicar Apostolic and he took up residence at Saint Mary's Cathedral in Sydney.
Fewer than ten years had elapsed, however, before settlement began to expand in parts of Australia other than New South Wales. Consequently, Rome augmented the arrangement of the Vicariate Apostolic with the establishment of the Archdiocese of Sydney and new Dioceses of Hobarton and Adelaide as suffragan dioceses. This was in 1842. John Bede Polding OSB became Archbishop of Sydney and Metropolitan of Australia.
As time progressed and Catholic populations grew, the following were established as suffragan dioceses of the Australian Province :
The Diocese of Perth, in 1845.
The Dioceses of Maitland and Melbourne, in 1847.
The Diocese of Port Victoria (now Darwin NT), in 1848.
The Diocese of Brisbane, in 1859.
The Dioceses of Goulburn and Armidale, in 1862.
The Diocese of Bathurst, in 1865.
As the population and economic standing of the Colony of Victoria grew, it was thought fitting that the Diocese of Melbourne be separated from Sydney in 1874, becoming a Metropolitan Archdiocese with the new Dioceses of Ballarat (Vic) and Sandhurst (Vic) established as suffragan dioceses. Its bishop, James Goold OSA, became Archbishop, of the same ecclesiastical rank as the Archbishop of Sydney.
Cairns (Qld) was established as a Vicariate Apostolic in 1877.
The Diocese of Rockhampton (Qld) was established in 1882, as a Suffragan of Sydney.
In 1887, as a consequence of deliberations of a Council of Australian bishops in 1885, new Ecclesiastical Provinces were established, further dividing the territory of the Archdiocese of Sydney :
The Archdiocese of AdelaideIn 1887, these new Dioceses were also established :
The Archdiocese of Brisbane.
The Diocese of Grafton (now Lismore NSW)In 1898 the Diocese of Geraldton (WA) was established, being a suffragan of the Archdiocese of Adelaide.
The Diocese of Broken Hill (now Wilcannia & Forbes NSW)
The Diocese of Sale (Vic)
The Diocese of Port Augusta (now Port Pirie SA)
The Vicariate Apostolic of the Kimberleys (WA)
From Wikipedia and the Code of Canon Law:
A suffragan diocese is one of the dioceses that constitute an ecclesiastical province. Although such a diocese is governed by its own bishop or ordinary (who is the suffragan bishop), the metropolitan archbishop has certain rights and duties of oversight pertaining to the suffragan dioceses. The Metropolitan has no power of governance within a suffragan diocese, but has some limited rights and duties to intervene in cases of neglect by the authorities of the diocese itself.