1792
In 1792 five Catholic lay people (four men and one woman) who were resident in Parramatta petitioned Governor Philip to appoint a priest to minister to them.

1803
In 1803 all the Catholics of colony were summoned to Parramatta on 20 April to hear a Proclamation by Governor King that Fr James Dixon was appointed to minister to Catholics.

The first official Mass was celebrated by Fr Dixon in Sydney on 15 May 1803 and in Parramatta on 22 May 1803 at an unknown site. Fr Dixon's appointment was later withdrawn following the "Vinegar Hill Rebellion" at Castle Hill in 1804.

1820
In 1820 Fr John Joseph Therry arrived in Parramatta. He set about obtaining a grant of land for a Catholic church and established the first Catholic school in Australia in Hunter Street, Parramatta.

Schoolhouse
The first church on the St Patrick's site was begun by Fr Power in 1827. It was still unroofed when Bishop Polding arrived in 1835 and, when finally completed, was a schoolhouse.

1836 Church
Bishop Polding laid the Foundation Stone on 17 March 1836. The church was consecrated on 28 May 1837.

1854 Church
By 1854 the existing church too small so Fr Coffey commissioned a larger church based on a design by AWN Pugin, but without the tower. The Foundation Stone of the site was registered on 24 August 1846 and laid on 13 August 1854.

Pugin Tower
Dean Rigney added the Pugin Tower, whose Foundation Stone was laid on 10 November 1878. The tower was consecrated on 17 March 1880. The spire was blessed in January 1883.

1936 Church
A new church was built in 1936 to meet the demands of a growing congregation. It incorporated the existing tower and spire. The Foundation Stone was laid on 26 May 1935 and the church opened on 31 May 1936.

1986 Diocese established
In 1986 the Diocese of Parramatta was established and St Patrick's Church was designated a Cathedral.

1996 fire
The Cathedral was destroyed by fire on 19 February 1996. The new St Patrick's Cathedral will be dedicated on 29 November 2003.