Described as an outstanding man ("vir egregius"), Kallistos 9 was the archdeacon of the church of Tarvisium (Treviso); on the death of the patriarch of Aquileia, Serenus 2, he was chosen as his successor, with the support of the Lombard king Liutprand 1: Paul. Diac., Hist. Lang. VI 45 ("Calistus, vir egregius, qui erat Tarvisianae ecclesiae archidiaconus, adnitente Liutprando principe, Aquileiensem ecclesiam regendam suscepit"). Later he was involved in a quarrel with the dux of Forum Iulii, Pemmo 1; because of Roman attacks, the patriarchs of Aquileia had been accustomed to live in Cormones Castrum, and not in Forum Iulii, which had become the home of the bishops of Castrum Iuliense (Iulia Carnica); Kallistos 9 refused to accept this; described as of noble character ("nobilitate conspicuus"), he objected to living in a humbler place when another bishop of his diocese (Amator 2) lived where the dux and the Lombards were; he therefore drove Amator 2 out of his house at Forum Iulii, which he then occupied himself; for this Pemmo 1 and other Lombard nobles seized him and carried him off to Castellum Potium, where after first threatening to throw him into the sea Pemmo 1 held him in custody; the Lombard king Liutprand 1 intervened and dismissed Pemmo 1 from office, but it is not recorded what became of Kallistos 9: Paul. Diac., Hist. Lang. VI 51.

(Publishable link for this person: )