SIRMIO, DIOCESE of. — In Bosnia. It has an area of 10,078 sq. km., with a population of 400,000 inhabitants, of whom 380,978 are Catholics, distributed among 4 archdioceses, 6 deaneries, and 111 parishes served by 135 diocesan and 27 religious priests; it has one seminary, 9 male and 48 female religious communities. The see is at Djakovo (Ann. Pont. 1952, p. 382).
S. (now Hrvatska Mitrovica), a city famous as the residence of emperors and praetorian prefects, was the capital of the province of Pannonia II. Christianity spread very early in this region, as is attested by many glorious martyrs, such as the “Four Crowned Ones” (v.), anonymous stonecutters from Fruska Gora, s. Polion, illustrious lector of the church of Cibale, and s. Irenaeus, heroic bishop of S. (d. in 304). Today, however, the ancient tradition—also upheld by Farlati—which attributes apostolic origins to the Church of S., is disputed. In the 4th century S. was the ecclesiastical metropolis of western Illyricum and later of Pannonia alone, with the suffragan bishops of Mursa (Osiek), Cibale (Vinkovci), and Vassiane (Petrovci?). In the Christological controversies, the bishops of S., Fotinus and the Arianizing Germinius, acquired the sad reputation of heresiarchs, while S. became famous at the time of the “seminary councils” held there concerning the celebrated “formulas of S.” S. was destroyed by the Avars in 582. After a long interval, a new city arose around the Eastern monastery of s. Demetrius, from which it took the name Dmitrovica, today Mitrovica, while S. (in Croatian: Sriem) remained the designation of the entire region between the Sava and Danube rivers. Hadrian II attempted in 869 to restore the archdiocese of S., with broad jurisdiction in the central Danube region, but the farsighted project of the Holy See could not succeed because of political intrigues. S. was restored only in 1229 by Gregory IX as an ordinary diocese, within fairly restricted boundaries. Its see was at the former Benedictine monastery at Banostar on the Danube; later the see was transferred to Mitrovica. The diocese suffered greatly because of heretical movements (first the so-called Bosnian heresy, then Hussitism and later, during Turkish rule, Calvinism, not to mention conversions to schism and Alamism, as well as the numerous immigrations). But with the liberation of this region from the Turks (1687–1735), all the groups disappeared except that of the “Orthodox.”
The city of Djakovo, with extensive possessions in Slavonia, most of which then belonged to the diocese of Pecuh (Pecs, Quinquecclesiae), was given by Duke Koloman in 1239 to the bishop of Bosnia. It was not long, however, before the bishop, threatened by the Patarenes, withdrew from Bosnia to Djakovo and remained there. Clement XIV united the dioceses of Bosnia in 1773 (in Bosnia proper there was the apostolic vicariate of Ottoman Bosnia) and S.; the new diocese, with its see at Djakovo, retained the twofold historical designation. At first it depended on the archdiocese of Kalocsa and later (from 1852) on that of Zagreb.
Among the distinguished bishops of Djakovo, the following should be remembered: Giorgio Palizna, killed by the Turks in the battle of Mohacs in 1526; Nicola Ogramic O. F. M., murdered by Orthodox brigands (1701); Antonio Mandio (1896–1915), founder of the Seminary of Djakovo; and finally Jopis Juraj Strossmayer (1850–1905), a famous speaker at the First Vatican Council, a noted propagator of ecclesiastical Union, a national tribune, a Croatian patron of the arts, founder of the Croatian University of Zagreb, and builder of the magnificent cathedral of Djakovo, in which the Romanesque and Byzantine styles are harmoniously fused.
The principal Marian shrines in the diocese are: Tekija, near Hrvatski Karlovci; Aljmas, near Osiek; and Ilaca. Notable monasteries and abbeys include: the Benedictine monastery at Banostar on the Danube (16th–17th centuries), a pious bequest of the Croatian ban Bjelos; and at Mitrovica, where, in the time of Innocent III, the exchange of the Greek monks took place; Cistercian monasteries at Petrovaradin and Osiek-Cikador (12th–15th centuries), destroyed during the Turkish invasion; and the Franciscan convents at Nasice (from 1321 to the present day) and at Ilok (from 1260 to today).