Named in La Tavola Ritonda as the Pope during Arthur’s reign.
When he heard of Tristan’s death, he offered indulgences to anyone who would pray for Tristan and his country. The text notes that he was succeeded by Pope Agabito. No known Popes correspond with these names, except perhaps Pope Donus and Pope Agatho, who ascended to the papacy in 676 and 678, respectively.
Source
La Tavola Ritonda | 1325–1350