Modestus was an Irishman by birth a disciple of St. Fergil. He may have come to the Bavarian lands under Duke Odilo in the wake of Fergil, who, about 749 was consecrated Bishop of Salzburg. Upon the request of Prince Cheitmar or Hotimir of Carantania to Christianize his people, Bishop Vergilius dispatched Modestus around the year 755, together with four priests and a deacon "and other inferior clerks" as a missionary with the rank of a chorepískopos, i.e. a chorbishop responsible for the people in the countryside. Modestus received authority as a bishop, but probably, after the Irish custom, was without a definite see. It is only in the late anonymous life of Gebhard of Constance, that he is called bishop of Liburnia. Cheitmar's predecessor Borut had accepted Bavarian overlordship about 740 and Modestus' missionary work in Carantania was meant to stabilise the country against the invading Avars. It was described in the "Conversio Bagoariorum et Carantanorum" written around 870 as a memorandum of the Salzburg archbishop Adalwin in a court hearing before the East Frankish kingLouis the German against Bishop Methodius, the apostle of the Slavs in the Frankish Principality of Lower Pannonia and in Great Moravia. In the document, the Archdiocese of Salzburg emphasised the achievements of Modestus as an argument of their merits in converting the Slavs. According to the chronicles, he built three Christian churches:
"ad Undrimas", spelt by the manuscripts in a variety of ways, believed to be a valley situated between S. Vitus and Maria-Saal;
at "Liburnia civitate", corresponding to the former Romanepiscopal see of Teurnia, the site of which is probably now marked by a field called Lurnfeld;
and "ecclesiam Sanctae Mariae", a church of the Virgin Mary in an unnamed place, most probably located near the centre of the Slav principality at Karnburg, which would make it Maria Saal on the Carinthian 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:
the Magdalensberg mountain where a large settlement dating from the Celtic Noricum kingdom is being excavated;
the remains of Roman Virunum, capital city of the later Roman province of Noricum, at the foot of Magdalensberg;
the Karnburg complex which served as the political centre of the Slav principality of Carantania, with the Prince's Stone nearby;
the modern capital of the State of Carinthia, Klagenfurt.
Modestus is said to have baptised St. Domitian, a Carinthian prince, at Milstadt, which may, perhaps, be identical with Adandrinas. According to the older manuscripts, Modestus stayed in Carinthia till his death; one late manuscript says he died in France. 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. Dempster calls him a companion of Saint Boniface, and Ferrarius says he is mentioned in Boniface's life. It is probable that in both cases St. Fergil was meant. A manuscript by him, 'ad ecclesiam suam,' was said to be at Salzburg, and a volume of his letters at Strasburg. Neither manuscript can now be traced.
Veneration
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 paganCarantanian Slavs to Christianity, Modestus was honoured by the popular denomination "Apostle of Carinthia". His feast is celebrated on 5 December.
