The accoutrements of a church usually cannot be refurbished by any party except the Church’s own recognized supreme authority, whatever that authority may be. In Northumbria in the seventh century of the Christian Era the abandonment of a traditional method of reckoning the date of Easter, which had survived in a Far Western Christendom, in favour of a novel method which was a Roman innovation, implied a recognition of the Roman Church’s supremacy over the churches of the “Celtic Fringe”. In a Western Catholic Christendom in the sixteenth century of the Christian Era the Julian Calendar – work of pagan genius though it was – could not have been reformed by any other authority than the Papacy; and the act of Pope Gregory XIII was as effective as it was uncharacteristic of the normally conservative êthos of an established universal church.
A Study of History, Vol VII, OUP, 1954
