The Diocese of Mostar-Duvno () is a particular church 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. Franciscan monasteries were destroyed and churches turned into mosques. In the 16th century, the last Franciscan monasteries perished in Herzegovina, however, they remained active among the Catholics. 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