The Diocese of Mostar-Duvno () is a Latin Church diocese of the Catholic Church in Bosnia and Herzegovina. It encompasses northern Herzegovina. The episcopal seat is in Mostar, Bosnia and Herzegovina. It was formed on 5 July 1881, when the Apostolic Vicariate of Herzegovina was elevated to the diocese. It is the largest Catholic diocese in Bosnia and Herzegovina by the number of Catholics.
The Diocese of Mostar-Duvno also retains the episcopal tradition from the Diocese of Duvno, an antique diocese first mentioned in 591, suppressed in the 7th century and reestablished in the 14th century.
The seat of the diocese is the Cathedral of Mary, Mother of the Church. The diocese releases a monthly magazine Crkva na kamenu.
The diocese covers area of , with 175,395 Catholics in 66 parishes of the diocese. There are 67 diocesan priests. The Franciscan Province of Herzegovina is serving 29 parishes.
The current bishop of Mostar-Duvno is Petar Palić. He also serves as Apostolic Administrator of Trebinje-Mrkan, which is administered by the bishops of Mostar-Duvno since 1890.
History
Roman Empire and the Middle Ages
During the Roman Empire, on the territory of the present-day Diocese of Mostar-Duvno, there were two dioceses: the Duvno and Narona-Sarsenterum. The Diocese of Duvno (Delminium) was first mentioned in 591, by Pope Gregory the Great. Venantius of Salona was martyred on the territory of the Diocese of Duvno in the 3rd century.
The Diocese of Duvno was suppressed in the 7th century, but re-established in 1337 by Pope Benedict XII as a defence against the Bosnian Church which was widespread in the Kingdom of Bosnia and was expending its influence on the territory of Croatia.
Ottoman rule
In 1482, Herzegovina was conquered by the Ottomans. Many people fled after the conquest or migrated later. In the 17th century, bishops in West Herzegovina were no longer present among the population, so the bishop of Makarska expanded his jurisdictions over West Herzegovina, including the Diocese of Duvno.
In 1709 and 1722, there were two petitions from the Catholics from Bosnia and Herzegovina to the Propaganda to send them a bishop that would reside among them. In 1722, the Propaganda tried to return the seat of the Bishop of Duvno that would have the jurisdiction over them, asking for the advice from the archbishops of Split and Zadar as well as the bishop of Makarska, however, they opposed claiming that the "Church of Duvno is canonically united" with their dioceses. On a session of the Propaganda from April 1722, it was concluded that the Propaganda could draw the new borders of the Diocese of Duvno, however, no further efforts were made on the matter.
The Catholics of Bosnia and Herzegovina continued sending the petitions to the Propaganda in 1723, 1729 and 1734. In 1734, the Propaganda started to study the matter inquiring about the status of Catholics in Bosnia and Herzegovina and the Diocese of Duvno. They asked the nuncio in Vienna, Austrian Empire to discuss the issue with the bishop of Bosnia who resided in Đakovo since the beginning of the 13th century, about establishing the new diocese. The Propaganda had another session on the matter in June 1735 and discussed the proposition of the Archbishop of Zadar about the reestablishment of the Diocese of Duvno. They also received an answer from the nuncio who informed them that the Austrian Emperor will not object to sending an apostolic vicar to Bosnia. Finally, the Propaganda agreed to grant the requests from the Catholics of Bosnia and Herzegovina, asking the archbishop of Zadar to propose them a suitable bishop.
The archbishop of Zadar made a suggestion that the jurisdiction of the apostolic vicariate should include the territory of the Diocese of Duvno, without an appointment of a special bishop of Duvno, in order to avoid the conflict with the archbishop of Split and bishop of Makarska. Finally, on 25 September 1735, Pope Clement XII granted the establishment of the Apostolic Vicariate of Bosnia.