Almost 90% of the city's population are Roman Catholics. Manila is the seat of the Archdiocese of Manila, the oldest archdiocese in the country, and the Primate of the Philippines. The archdiocese's offices is located in the Manila Cathedral (Basilica Minore de la Nuestra Señora de la Immaculada Concepcion) inside the Intramuros. The city celebrates it's foundation day every 24 June, hence it is under the patronage of John the Baptist.
Today, aside from the Manila Cathedral (also known as the Basilica Minore de la Inmaculada Concetion), Manila is also home to 3 other basilicas, the Basilica of the Black Nazarene and the Basilica Minore de San Sebastian.
Being the seat of the Spanish colonial government in past centuries, it has been used as the base of numerous Roman Catholic missions to the Philippines. Among the religious orders that have gone to the Philippines include the Dominicans, the Jesuits, the Franciscans, the Augustinians, the Augustinian Recollects, the Benedictines, the Sisters of St. Paul of Chartres, the Vincentian Fathers, the Congregatio of the Immaculati Cordis Mariae, and the De La Salle Christian Brothers.
Other notable churches in the city include San Agustin Church in Intramuros, the shrine of the canonically crowned image of Nuestra Señora de Consolación y Correa, a UNESCO World Heritage Site, and a favorite wedding place of notable people and one of two fully air-conditioned churches in the city; the Binondo Church, also known as Basilica Minore de San Lorenzo Ruiz; Malate Church, the shrine of Nuestra Señora de Remedios; Ermita Church, home of the oldest Marian Image in the Philippines, Nuestra Señora de Guia; Tondo Church, home of the century-old ivory image of Sto. Niño (Child Jesus); and Sta. Ana Church, shrine of the canonically crowned image of Nuestra Senora de los Desamparados.
Source: Wikipedia Encyclopedia