Roman Catholic Diocese of Quilon

The Diocese of Quilon (Latin: Diœcesis Quilonensis) is a Latin Church ecclesiastical jurisdiction or diocese of the Catholic Church based in the southern Indian city of Kollam. It is a suffragan in the ecclesiastical province of the metropolitan Archdiocese of Trivandrum. The Diocese of Quilon covers an area of 1,950 km² (753 square miles) that contains a population of some 4.8 million. At least 4.8% of the people in the area are Catholic.

The history of the Roman Catholic Church in Quilon begins with the erection of a diocese on 9 August 1329. This diocese was later suppressed. The present day Diocese of Quilon was established as an apostolic vicariate on 15 March 1853 by bifurcating the Apostolic Vicariate of Verapoly. It was elevated as a diocese on 1 September 1886.

As of 18 April 2018^[update], Paul Antony Mullassery is the bishop of the Diocese of Quilon.

According to tradition, St. Thomas the Apostle established seven churches along the southern part of west coast of India, and Quilon (pronounced Koy-lon) is the second in the list of the above seven churches.

John of Monte Corvino, a member of the Societas Peregrinantium Pro Christo on his way to China, landed in Quilon in 1291 and ministered the Christian community. The Venetian traveller Marco Polo who visited India in 1292 testified to the presence of a Christian community in Quilon.

Since the latter half of the 13th century, Quilon became the chief centre of missionary expeditions. Franciscan and Dominican Missionaries in the 13th and 14th centuries visited Quilon and their letters confirm the existence of a vibrant Christian community in Quilon.

In 1329 Pope John XXII, from the Holy See then in Avignon (France), erected Quilon as the first Diocese in the whole of Indies as suffragan to the Archdiocese of Soltaniyeh in Persia through the decree "Romanus Pontifex" dated 9 August 1329 By a separate bull, "Venerabili Fratri Jordano", the same Pope, on 21 August 1329 appointed the French or Catalan Dominican friar Jordanus Catalani as the first Bishop of Quilon.

(Copies of the Orders and the related letters issued by Pope John XXII to Bishop Jordanus Catalani and to the diocese of Quilon are documented and preserved in the diocesan archives. Also reprinted in the Indian Church History Classics, Vol.I, The Nazranies, South Asia Research Assistance Services, Ed. Prof. George Menachery, Ollur, 1998.)