Construction starts on St. Malachy's Church, the first Roman Catholic Church in Saint John.

Nearly 30,000 Irish refugees are delivered to the shores of Saint John, more than doubling the population of the city.

Initial plans instituted by Bishop William Dollard for the construction of a new cathedral.

Bishop Connolly arrives in Saint John, building a place of worship, schools, and an orphanage run by the Sisters of the Sacred Heart. He also founds the Sisters of Charity under Honoria Conway and helps the Irish community gain acceptance. He announces plans for a cathedral on land purchased from Hazen and Hammond.

Plans for the Cathedral are prepared by Charles F. Anderson in New York during the winter of 1852-1853. Contract for excavation work is awarded to William Smith.

Cornerstone laid in May, and by November the walls are up, and the roof laid.

Mass is celebrated for the first time in the new Cathedral by Bishop Connolly, with 3,000 in attendance. There are no pews, no lights, no heat.

Bishop Connolly appointed Archbishop of Halifax.

The Rt. Rev. Dr. John Sweeny is appointed Bishop of Saint John. He completes the Cathedral of the Immaculate Conception, secures religious orders, and establishes educational and charitable institutions, including orphanages, a school, a home for the elderly, and a college. He also expands the diocese with new parishes and missions, tripling the number of priests from 1860 to 1895.

The chapel, chancel, and entrances are completed, and the adjacent Bishop's Palace is built.

The spire is erected on the Cathedral reaching 230 feet, or 300 feet above sea level, the highest point in the city. The Cathedral's interior is 200 feet long, with transepts at 116 feet and the nave at 80 feet.

The consecration of the Cathedral takes place, and the main structure is completed.

The Cathedral's 100th anniversary is celebrated. On March 23, Bishop Alfred B. Leverman reconsecrated the original altar, first consecrated on July 16, 1885. Relics of St. Martin, St. Andrew, St. Barnabas, and St. Ambrose were placed in the new altar stone.

Major renovations take place: stonework was sandblasted and weatherproofed, interior repainted, heating system rezoned, archway of chapel enclosed, original stained-glass windows re-leaded, and sanctuary renovated.

The 100^th anniversary of the consecration of the Cathedral of the Immaculate Conception celebrated.

Upper tower internal concrete structure and partial steel frame are installed.

Cathedral celebrates 170th year of consecration (July 16) and the first Mass (December 24) in the context of the Jubilee Year, Pilgrims of Hope.