Antipope Constantine II (d. 769[?]) was an Italian man who claimed the title of Pope in Rome in 767. The most powerful Lombard authorities considered his papacy invalid, and in spring 768 they deposed and imprisoned him. He was blinded in August after a rebellion attempted to restore him to power. In April 769, the Lateran Council had Constantine's tongue cut out for perjury. He was returned to prison, but the manner of his death is unknown.
Constantine II in "Islands in the Sea"
In AD 769, at the request of the heathen Bulgar Khan Telerikh, Pope Constantine sent Fathers Niketas and Theodore, and Brother Paul to describe the merits of Christianity. Telerikh was trying to decide whether to adopt Christianity or Islam for his people.
The text does not clarify whether "Pope Constantine" (no numeral given) is the same man as Antipope Constantine II. He is treated as such for convenience.
- See e.g. Departures, pg. 68.
(reign unrecognized, claim declared invalid as "Antipope")