7th-century missionary, Archbishop of Canterbury, and saint
Justus (died on 10 November between 627 and 631) was the fourth archbishop of Canterbury. Pope Gregory the Great sent Justus from Italy to England on a mission to Christianise the Anglo-Saxons from their native paganism; he probably arrived with the second group of missionaries despatched in 601. Justus became the first bishop of Rochester in 604 and signed a letter to the Irish bishops urging the native Celtic church to adopt the Roman method of calculating the date of Easter. He attended a church council in Paris in 614.
https://en.wikipedia.org/wiki/Justus