Time Line: 1991
- beatification of Blessed Adolph Kolping
- beatification of Blessed Edoardo Giuseppe Rosaz
- beatification of Blessed Joseph Sebastian Pelczar
- beatification of Saint Pauline of the Agonizing Heart of Jesus
- declaration of Blessed Gianna Beretta Molla as Venerable
- declaration of Blessed Laura of Saint Catherine of Siena as Venerable
- declaration of Blessed Maria Anna Blondin as Venerable
- declaration of Blessed Mark of Aviano as Venerable
- declaration of Blessed Marie Poussepin as Venerable
- declaration of Blessed Peter Higgins as Venerable
- declaration of Blessed Terrence Albert O'Brien as Venerable
- declaration of Emmanuel D'Alzon as Venerable
- declaration of John Henry Newman as Venerable
- declaration of Laura of Saint Catherine of Siena as Venerable
- declaration of Oreste Fontanella as Venerable
- declaration of Vincent Cimatti as Venerable
- elevation of the archdiocese of Alba Iulia, Romania
- elevation of the diocese of Alto Solimões, Amazonas, Brazil
- elevation of the diocese of Jinotega, Nicaragua
- elevation of the diocese of Juigalpa, Nicaragua
- elevation of the vicariate apostolic of Meki, Ethiopia
- founding of the apostolic administration of European Russia
- founding of the apostolic administration of Kazakhstan
- founding of the apostolic administration of Lubaczów, Poland
- founding of the apostolic administration of Siberia, Russian Federation
- founding of the diocese of Alcalá de Henares, Spain
- founding of the diocese of Bialystok, Poland
- founding of the diocese of Cachoeira do Sul, Rio Grande do Sul, Brazil
- founding of the diocese of Drohiczyn, Poland
- founding of the diocese of Ebolowa-Kribi, Cameroon
- founding of the diocese of Fort-Liberté, Haiti
- founding of the diocese of Getafe, Spain
- founding of the diocese of Gokwe, Zimbabwe
- founding of the diocese of Grodno, Belarus
- founding of the diocese of Kotido, Uganda
- founding of the diocese of Melipilla, Chile
- founding of the diocese of Nacala, Mozambique
- founding of the diocese of Yokadouma, Cameroon
- founding of the Armenian ordinariate of Eastern Europe
- founding of the military ordinariate of Poland
- founding of the mission "Sui Iuris" of Bomadi, Nigeria
- founding of the mission "Sui Iuris" of Kano, Nigeria
- founding of the vicariate apostolic of Mandeville, Jamaica, Antilles
- coup d'état in Thailand
- cyclone hits Bangladesh killing 138,000 people
- Dead Sea Scrolls made available to the public
- eruption of Mount Pinatubo, Philippines
- Persian Gulf War to liberate Kuwait
- Soviet Union officially dissolved
- Warsaw Pact dissolved
- World Web Web comes online
