The caption above tells two of his alleged puns, but in between the one about Angles/Angels and AElla/Alleluia he also punned on the name of Aella’s kingdom – Deira in Northumberland,saying he would save them from the wroth of God (de ira in Latin).
He sent St Augustine to Canterbury to convert the English. It is possible to argue that this encounter is why we are called English, because St Augustine was sent to set up the Church of the Angles, or the Anglish/English Church, not the Saxon Church. Eventually, the term became a relatively neutral term that the various shades of Germanic peoples in Britain could unite under.
The mission was sent in AD 597 and Pope Gregory died in AD 604.