Modestus (c. 720 – before 772),[1] called the Apostle of Carinthia, Apostle of Carantania, was most probably an Irish monk and the evangelizer of the Carantanians, an Alpine Slavic people in the south of present-day Austria and north-eastern Slovenia, which were among the ancestors of present-day Slovenes.
Upon the request of Prince Cheitmar or Hotimir[2] of Carantania to evangelize his people, Modestus was dispatched around the year 755 by bishop Vergilius of Salzburg, together with four priests and a deacon "and other inferior clerks"[3] as a missionary with the rank of "choroepiskopos", i.e. a bishop responsible for the people in the countryside without a diocese,[4] to the Carantanians. According to sources, he built three Christian churches there: "ad Udrimas" (probably in the Judenburg area in present-day Styria), at "Liburnia", corresponding to the former Roman bishop seat of Teurnia, today's Sankt Peter im Holz near Spittal an der Drau, and a church of the Virgin Mary in an unnamed place, most probably located near the centre of the Slav principality at Karnburg (Slovene: Krnski grad), which would make it Maria Saal (Slovene: Gospa sveta) on the Zollfeld plain.
His church was thus in the immediate vicinity of the area that has served as a political and cultural centre of the region through the ages, close to:
Modestus spent the remainder of his obviously very active life in the area. The most likely year of his death was 763, although other dates also appear in sources. No traces of his church of St.Mary have been discovered. His alleged tomb is shown in the present Gothic church of Maria Saal, which was built six centuries later, replacing an earlier Romanesque church probably from the 12th century. Due to his success in converting the pagan Carantanian Slavs to Christianity, Modestus was honoured by the popular denomination "Apostle of Carinthia". His missionary work was described in the "Conversio Bagoariorum et Carantanorum"[5] written in Salzburg around 870, as a memorandum of the archbishops of Salzburg in a court hearing before Emperor Louis the German against bishop Method, the apostle of the Slavs in Pannonia and Moravia, at Ratisbon, (German: Regensburg) in 870. In the document, the Archdiocese of Salzburg emphasized the achievements of Modestus as an argument of their merits in converting the Slavs.