In 1678, Louis Hennepin, accompanying French explorer René-Robert La Salle, celebrated the first mass in present day Buffalo.

[5] Richard Coote, the first colonial governor, passed a law at the end of the 17th century that mandated a life sentence to any Catholic priest.

Stephen Badin, a missionary from Kentucky, spent six weeks in Buffalo as the guest of Louis Le Couteulx, a French businessman.

[4] Dubois sent Mertz to Europe to raise funds for the diocese and dispatched John Neumann to Buffalo in 1836 to assist Pax.

Thomas McEvoy of Java worked with Catholics in Allegany, Wyoming, Steuben, and Chautauqua counties in the Southern Tier of New York.

[15] The Grey Nuns order in 1865 founded The Holy Angels Infirmary Academy for girls in Buffalo; it would eventually become D'Youville University.

The Association paid these men through saloon keepers, who would subtract charges for room, board and drinks from the workers' wages, leaving them very little.

While claiming to support the union movement, Quigley denounced socialism and gave his interpretation of why the Catholic Church opposed it.

[29] During his tenure, the diocese had 72 churches, 18 combination school-churches, 30 schools, 12 academies, 13 hospitals and charitable institutions, six convents, and 28 rectories.

[34]: 110  During his tenure, he also established 15 new parishes and supported the World War I effort through liberty bond campaigns and Red Cross drives.

Turner was a supporter of the Society of Saint Vincent de Paul, and in 1924 began a Catholic Charities chapter in Buffalo.

[38] During his tenure, Duffy established the Diocesan Fund for the Faith for those impacted by the Great Depression and erected parishes in rural areas of the diocese.

During his 10-year-long administration, Burke supported Holy Name Society, missions, the Pre-Cana program, Puerto Rican migrants, and displaced persons.

He also continued the expansion and construction of educational institutions, including St. John Vianney Seminary in East Aurora, New York.

[51] In 2007, Kmiec announced that the diocese had a balanced budget, after spending cuts reduced a $2.1 million deficit from the previous year.

Pasquale had gone to the Erie County District Attorney's Office prior to his dismissal to raise concerns about questionable financial practices in the diocese.

"[58]In September 2019, leaked audio recordings of Malone revealed that he had diverted 40 percent of donations sent to Catholic Charities in the diocese to a foundation known as "The Bishop's Fund for the Faith.

"[59] The foundation was included in the diocese's budget as a separate corporate entity, which would protect the money from lawsuits and bankruptcy filings.

[61][62] 60 Minutes Overtime reported that month that Malone's resignation was linked to documents leaked in 2018 by his executive assistant, Siobhan O'Connor, detailing his concealment of sexual abuse by priests.

[76] In 2011, Bishop Kmiec suspended Art Smith, a priest who taught at St. Mary of the Lake School in Hamburg, from ministry.

The school principal had asked the diocese to remove Smith after he posted a love message to an eighth grade boy on Facebook.

Michael F. Whalen Jr in February 2018 accused the priest Norbert F. Orsolits of sexually assaulting him in 1979 or 1980 during a ski trip.

[77] When interviewed by a Buffalo News reporter after Whalen's statement, Orsolits admitted to sexually abusing dozens of boys during his career, but claimed it was consensual.

[84][85][86] In September 2018, Malone named Steven L. Halter, a former FBI investigator, as director of the diocese's newly created Office of Personal Responsibility, tasked with handling sex abuse complaints.

[90] In May 2019, Paul K. Barr sued the diocese, claiming that he had been sexually abused by the priest Michael Freeman, then posted at Sacred Heart Parish in Niagara Falls.

[94] That same month, the diocese published an Adult Sexual Misconduct Policy and Procedures and a new Code of Pastoral Conduct for Clergy.

In 2012, after having consumed alcohol at a dinner with a young man, Salemi suggested that he stay the night with him and engage in oral sex.

[101][102] In November 2020, New York Attorney General Letitia James sued the diocese, Malone, and Auxiliary Bishop Edward M. Grosz.

The Office of the Attorney General released a 218-page report detailing the results of a two-year investigation into all the parties named in the lawsuit.

[104] The Diocese of Buffalo includes the following eight counties in Western New York State:[3] The seminary was founded in 1857 as part of the new St. Bonaventure College in Allegany.