1780
Catholic Scotsmen, with their priests, settle in the area that becomes the parishes of St. Andrew, in Stormont county and St. Raphael, in Glengarry county.
1826
The Diocese of Kingston is established and Reverend Alexander Macdonell, the third pastor of St. Raphael’s, is appointed the first Bishop of Kingston on January 27th. His residence remains in St. Raphael until 1829.
1890
The Diocese of Alexandria is established on January 23rd and comprises Stormont and Glengarry counties. The Diocese remains part of the ecclesiastical province of Kingston. Reverend Alexander Macdonell, named after the first bishop of Upper Canada, is chosen as the new Diocese’s first bishop.
1909
Bishop William Macdonell, the Diocese’s second bishop, establishes the parish of Sacré-Coeur to serve the French-speaking population of Alexandria. He blesses the cornerstone on April 10, 1910.
1921
Following the death of Bishop William Macdonell, the French-born, British raised Felix Couturier, becomes the Diocese’s third bishop. He oversees the Diocese through both the Great Depression and the first few years of WWII.
1941
Rosario Brodeur is named the Diocese’s fourth bishop. During his
episcopate, many churches are built and the number of vocations rises.
1963 – 1965
Bishop Brodeur attends the four sessions of Vatican II.
1972
The Diocese’s fifth bishop, Adolphe Proulx, oversees the preparation and carrying out of the 1972 Diocesan Synod whose purpose is to implement the recommendations of Vatican II. There are five hundred participants.
1976
On September 17th, Eugène LaRocque, the Diocese’s sixth bishop, is granted permission by the Sacred Congregation for Bishops to affix the name Cornwall to Alexandria and to have Nativité as a co-cathedral.
1990
The Diocese of Alexandria-Cornwall celebrates its 100th anniversary.
2002
The Diocese welcomes its 7th bishop, Paul-André Durocher. During his episcopate, Bishop Paul-André must deal with a number of turbulent issues including the abuse scandals and the closing of several parishes.
2015
Under the guidance of the 8th Bishop, Marcel Damphousse, the Diocese celebrates its 125th anniversary as it sets its sights on the future.
2016
Bishop Marcel bids farewell to the Diocese to take up his new
assignment with the Diocese of Sault Sainte Marie. Archbishop Terrence Prendergast, S.J. is named Apostolic Administrator of the Diocese
2018
On April 27, 2018, the Holy Father, Pope Francis, united, in persona episcopi, the Diocese of Alexandria-Cornwall with the Archdiocese of Ottawa, and appointed H.E. Terrence Prendergast, S.J., archbishop of Ottawa and bishop of Alexandria-Cornwall.
2019
Guy Desrochers, C.Ss.r., is ordained on February 22nd as the auxiliary bishop for Alexandria-Cornwall.
2020
On May 6, 2020, the Diocese of Alexanria-Cornwall and the Archdiocese of Ottawa were canonically amalgamated by Pope Francis to form the new Archdiocese of Ottawa-Cornwall.