When Melbourne's first Catholic priest, Patrick Bonaventure Geoghan, arrived in May 1839 the Port Phillip Gazette described his flock as mostly working-class and Irish. Neither designation was completely accurate. In the early years their number included a wealthy Englishman, Edward Curr (the first to encounter electoral sectarianism); a number of Scots (including Alexander, father of Mary MacKillop); Irish patricians (including two early premiers, John O'Shanassy and Charles Gavan Duffy); and many who displayed marked social mobility, like Peter Lalor, the Eureka rebel who rose to be Speaker of the Legislative Assembly.
Although the community had its differences, particularly in the late 1850s when some of the laity sought control over finances, the withdrawal of state support for denominational schools forged Catholic unity against what was seen as the 'godless' secular system. Religious orders (especially the Christian Brothers and the Sisters of Mercy) garnered the popular financial support that made Catholic education and consequent social mobility possible.
Despite this apparent unity, there were significant areas of tension. By 1900 less than 7% of Catholics were from Ireland, though the clergy were still mostly Irish. Recurring episcopal disapproval of 'mixed marriages' and sympathy for Irish causes fuelled sectarianism, which was further exacerbated by the role played by Archbishop Daniel Mannix during the conscription debates of World War I. By contrast, despite the social encyclical Rerum Novarum (1890), the hierarchy was slow to support Catholic involvement in the emerging labour movement, warning against the dangers of 'socialism'. Working-class parishes like St Ignatius Richmond developed links with both the nascent Australian Labor Party (ALP) and Australian Rules Football, but there was further dissension during the 1950s Labor 'Split' when many Catholics joined B.A. Santamaria in the new Democratic Labor Party, while others like Arthur Calwell and Senator P.J. Kennealy remained within the ALP.
Melbourne's first bishop, James Alipius Goold, an Irish Augustinian friar, arrived in 1848. A diligent pastor, he was succeeded in 1883 by an Irish bishop of landed gentry background, Thomas Joseph Carr, an able Catholic apologist. The third incumbent, Archbishop Daniel Mannix, was less concerned about social integration than his predecessors. His eloquent championing of popular Catholic causes made him a cult figure throughout Australasia. These three archbishops, covering 115 years, gave great continuity to the archdiocese. Melbourne Catholicism has also made a major contribution to the city's built environment with St Patrick's Cathedral, St Francis' and St Augustine's. In the suburbs Neo-Gothic dominated Victorian architecture, but many later buildings were more bland and functional.
A major beneficiary of postwar immigration, the Catholic population grew from 250 000 in 1940 to 978 844 in 1991. More culturally diverse than that of any other denomination, it also encompasses other churches in communion with Rome, the most prominent of which is the Ukrainian Church with its cathedral in Dryburgh Street, North Melbourne. Catholics worshipped in Latin until the liturgical changes that followed Vatican II fragmented this uniformity. The brief tenure of Justin Symonds, followed by those of James Knox and Thomas Francis Little, saw the implementation of many of these reforms. The next archbishop, Dr George Pell (Archbishop of Melbourne 1996-2001), who achieved a high profile, shared, with his successor Denis Hart, a firm commitment to Catholic unity within this diverse community. In a country shaped by Enlightenment attitudes relegating religion to the private domain, Melbourne Catholicism remains part of the public discourse.
From 1951 to 2004, the number of clergy (diocesan and religious) increased from 435 to 663 but the Catholic population has more than trebled. Sunday mass attendance declined from 232 000 in 1984 to 180 000 in 1996, and confidence has been challenged by sexual scandals involving Church personnel. The Church remains committed to its education and social services, maintaining hospitals, children's homes, aged care facilities and disability services. Voluntary organisations such as Jesuit Social Services, the St Vincent de Paul Society and local groups work to alleviate poverty, and there is a vigorous commitment to missions and Aboriginal welfare. Many of these organisations were initiated by religious communities such as the Sisters of the Good Shepherd and the Little Sisters of the Poor, with the work now continued by the lay community.