| Sept. 7 1828: |
Approval is given for the building of a first wooden church: Saint James. The church is in fact built only in 1832 on the site of the present cathedral. |
| In 1842 : |
A new larger stone church building is erected on the same site. It will be dedicated to the Immaculate Conception of the Virgin Mary in 1853. |
| Jan. 24 1844: |
Father. Adrien Telmon, first Oblate of Mary Immaculate, arrives from Montreal. |
| Feb. 20 1845: |
Arrival of Sister Elizabeth Bruyère and her companions from Montreal. They will become the Sisters of Charity of Ottawa. |
| Jun. 25 1847: |
Foundation of the diocese of Bytown. It will serve the population on both sides of the Ottawa River formerly under the jurisdiction of either the diocese of Montreal or the diocese of Kingston. |
| Jul. 30 1848: |
Ordination of Bruno Guigues o.m.i. as first bishop of Bytown. In September, St Josephs College founded by the new bishop opens its doors. |
| Mar. 7 1850: |
Inauguration of pipe organ at Notre Dame Cathedral. |
| Jul. 12 1854: |
Arsonists destroy St. Michael's chapel in Fitzroy Harbour. |
| Jun. 14 1860: |
The Diocese of Bytown become the Diocese of Ottawa. |
| Oct. 21 1866: |
Bishop Guigues dedicates the first church of Saint Patrick in Fallowfield. That same year, St Josephs College, now known as the College of Ottawa, receives a university charter. |
| Apr. 15 1869: |
Sisters of the Congregation of Notre Dame (CND) establish their first house. |
| Aug. 12 1869: |
Sisters of Charity open Rideau St. Convent. |
| Oct. 6 1872: |
Bishop Guigues blesses Saint Patrick's Church cornerstone in Ottawa, laid by Prime Minister Sir John. A. Macdonald. |
| Nov. 3 1872 : |
Bishop Guigues blesses Saint Jean-Baptiste church,on Empress Ave, Ottawa. |
| Feb. 8 1874: |
Death of Bruno Guigues, OMI, first bishop. |
| Oct. 28 1874: |
Joseph-Thomas Duhamel ordained as bishop of Ottawa. |
| Mar. 14 1875: |
Blessing of St. Patrick's Church. |
| Aug. 19 1879: |
Notre Dame Cathedral elevated to rank of Basilica. |
| Aug. 24 1884: |
The Dominican Friars take charge of Saint Jean-Baptiste parish. Their monastery will eventually develop into the Dominican Studium in 1900 for the teaching of philosophy and theology. |
| Jun. 8 1886: |
Pope Leo XIII makes the diocese of Ottawa an archdiocese. |
| Aug. 5 1888: |
Archbishop Duhamel opens first Synod of Ottawa. |
| Feb. 4 1889: |
Pope Leo XIII declares Ottawa University a Pontifical University. |
| Jul. 1 1890: |
Friars Minor (Capuchins) arrive to found St. Francis of Assisi Parish. |
| Jan. 23 1900: |
The first Knights of Columbus council is founded. |
| Jun. 5 1909: |
Death of Archbishop Thomas Duhamel. |
| Sept. 6 1910: |
Charles-Hugues Gauthier, archbishop of Kingston, is appointed to the Archdiocese of Ottawa. |
| Mar. 27 1913: |
First issue of Le Droit newspaper, founded by the Oblate Fathers. Its aim is to promote French-language school rights that are threatened by the government of Ontario. |
| Feb. 8 1919: |
The Franciscan Fathers arrive in Ottawa. |
| Jan. 24 1922: |
Death of Archbishop Charles-Hugues Gauthier. |
| Jun. 2 1922: |
Bishop Joseph-Médard Émard of Valleyfield becomes Archbishop of Ottawa. |
| Sept. 20 1925: |
Creation of the Diocesan Seminary on Rideau St. Father Joseph Charbonneau is named first superior. |
| Jan. 26 1926: |
Papal approval is given for the formation of the Grey Sisters of the Immaculate Conception. |
| Sept. 4 1926: |
The Grey Sisters open Immaculata High School. |
| Mar. 15 1926: |
Establishment of St. Peter's Province of the Oblates of Mary Immaculate. |
| Mar. 22 1927: |
Death of Archbishop Joseph-Médard Émard. |
| Jan. 29 1928: |
Bishop Guillaume Forbes of Joliette becomes Archbishop of Ottawa. |
| Sept. 5 1929: |
Saint Patrick's College is opened by the Oblates of Saint Peters province. |
| Jan. 1 1937: |
The Oblates found Saint Paul Seminary on Main street. |
| May 22 1940: |
Death of Archbishop Guillaume Forbes and appointment of his coadjutor, bishop Alexandre Vachon, as Archbishop of Ottawa. |
| May 19 1947: |
Opening of the International Marian Congress on the occasion of the centennial celebrations of the Archdiocese of Ottawa. |
| March 30 1953: |
Sudden death of Archbishop Alexandre Vachon. |
| June 20 1953: |
Bishop Marie-Joseph Lemieux from Gravelbourg, Saskatchewan, is appointed Archbishop of Ottawa. |
| Sept. 1955: |
Opening of the new campus of Le Petit Séminaire d'Ottawa, on Carson Rd. Father Charles-Decembere Demers is superior since 1954. |
| Sept. 1957: |
Opening of the Major Seminary of Ottawa on Kilborn Ave, to serve both French-language and English-language students of the diocese in theology. Father Delphis Rollin is the superior since 1954. |
| Sept. 1958: |
Creation of Saint Pius X Seminary on Fisher Ave. Nepean, under the direction of the diocesan clergy. |
| Jul. 13 1960: |
Archdiocese founds Tupi Paulista mission in Brazil. |
| April 27 1963: |
Creation of the Diocese of Hull: Paul-Emile Charbonneau, auxiliary bishop of Ottawa, becomes the founding bishop. The territory of the new diocese consists of the Quebec part of the Archdiocese of Ottawa. |
| Jul. 1 1965: |
The University of Ottawa obtains a new civil charter from the government of Ontario, under lay leadership. Saint Paul University is created out of the religious faculties of the University of Ottawa. |
| Feb. 26 1967: |
Bishop Joseph-Aurèle Plourde, apostolic administrator of the diocese of Alexandria, becomes Archbishop of Ottawa. Archbishop Lemieux has been appointed papal nuncio to Haiti. |
| Jul. 12 1967: |
Saint Patrick's College becomes affiliated to Carleton University. |
| Apr. 6 1968: |
The Sister of Charity close Bruyère College. |
| Feb. 16 1969: |
Archbishop J. A. Plourde opens diocesan synod. |
| Nov. 6 1980: |
The Sisters of Charity found the Elizabeth Bruyère Health Centre, renovating the facilities of the old Ottawa General Hospital. |
| Aug. 1984: |
The offices of the Diocesan Centre are relocated in the building of the former Major Seminary on Kilborn Ave. One wing of the building also houses the John Paul II Residence for retired priests. |
| Sept.19-20 1984: |
Visit of Pope John Paul II. |
| Feb. 11 1988: |
Father Robert Bédard founds the Companions of the Cross. |
| Sept.17 1988: |
Mother Teresa of Calcutta visits the Archdiocese |
| Sept.27 1989: |
Marcel Gervais, bishop of Sault Sainte-Marie, succeeds J.A. Plourde as Archbishop of Ottawa. |
| Oct. 17 1993: |
Archbishop Gervais begins first year of diocesan synodal process. |
| Mar. 17 1995: |
Pope John Paul II raises Saint Patrick's Church in Ottawa to the status of Basilica. |
| May 31, 1997: |
Launch of the 150th anniversary of the establishment of the Diocese of Ottawa |