On 3rd April, 1845 : Coimbatore was announced and established as a new diocese, which was part of Pondicherry diocese till then.
First Bishop      :       Bishop Marion de Bresillac.
24th July,1849  :       Bishop Marion de Bresillac decided to erect a new cathedral for the diocese.
15th Aug, 1850 :      Bp.Bresillac along with Bp.Paasi Nelli decided the blueprint of the new cathedral.
1850                   :      Bp.Bresillac laid the foundation stone (took 17 years to complete the construction work)
28th April,1867 :      Bp.Thepomeo consecrated the cathedral.
Sep,1873           :      Bp.Thepomeo died and his body was buried in the cathedral.
23rd Aug,1874  :      Bp.Joseph Bardou was the new bishop of the diocese
7th Feb, 1903    :      Bp.Joseph Bardou died.
1903                   :       Fr.Dennis Peiramal was chosen as the Bishop.
17th Aug, 1903  :      Bp.Dennis Peiramal died.
                                    Fr.Rondy was the incharge of the cathedral till the new bishop was ed.
28th Dec,1903  :      Bp.Augustin Roy was chosen as the bishop.
12th Feb,1904   :      Bp.Augustin Roy was consecrated as bishop.
12th Jan.1931    :     Bp.Augustin Roy resigned his episcopacy.
21st Dec,1937   :     Bp.Augustin Roy died.
25th May,1987    :     Bp.Augustin Roy's body remains were buried in the cathedral.
1940                     :    Bp.Oubagarasamy was the first Indian bishop.
1947                     :    centenary year of the diocese.
26th April,1950   :     Bp.Francis Savarimuthu.
1954                     :     His Eminence.Cardinal Valerian Gracias visited the diocese for the first time.