The use of heraldry in the Church was a tradition developed by the clergy firstly to mark documents and identify people and dioceses. In English heraldry there are strict rules as to the forms and styles which make up a Coat of Arms. The College of Arms is responsible for the enforcement of standards in England, whereas Lord Lyon is the officer charged with ensuring compliance in Scotland and Ulster King of Arms covers Ireland.
Arms of the Dioceses in the Province of Canterbury
Bath & Wells
St Edmundsbury & Ipswich
Gibraltar in Europe
Arms of the Dioceses in the Province of York
Sodor & Man
Southwell & Nottingham
Arms of an Archbishop
Anglican bishops in England generally place a mitre over their shield. The exception to this rule being the Bishop of Durham who, being a palatinate bishop (bishop in a county whose lord had regal powers) has his mitre in a ducal coronet. That is a coronet decorated with three strawberry leaves.
The arms of the Archbishop of Canterbury. Heraldic description - Azure, an archiepiscopal staff in pale argent ensigned with a cross-pattee or, surmounted of a pall of the second edged.
Here we see the personal arms of an Archbishop impaled with the arms of the See of Canterbury.