Augustine's fear

I have been reading Bede's Ecclesiastical History of the English People which was written about 731AD. It is the account of how God's word came to Briton through Augustine at the end of the 5th century and the continual and rapid expansion of the church through Bede's time 300 years later.

After encountering some very light skinned, blue-eyed slaves from Briton, Pope Gregory was greatly moved by these 'angelic' looking pagans from the North. He desired to bring the Gospel to these people, so he sent Augustine and several other monks to Briton to bring Christ to the pagans. When Augustine arrived in Briton he and the others immediately felt unable to accomplish the mission amidst the fierce barbarianism they found there. They sent Augustine back to Rome to ask Pope Gregory if they could return. Gregory wrote a letter of encouragement and perseverance which Augustine took back with him to the others. They remained in Briton spreading the Word of God and establishing the first churches in Briton.