The collect for today, the Feast of Saint Augustine (d. c. 605), first Archbishop of Canterbury (source):
O Lord our God, who by thy Son Jesus Christ didst call thine apostles and send them forth to preach the Gospel to the nations: We bless thy holy name for thy servant Augustine, first Archbishop of Canterbury, whose labors in propagating thy Church among the English people we commemorate today; and we pray that all whom thou dost call and send may do thy will, and bide thy time, and see thy glory; through Jesus Christ our Lord, who liveth and reigneth with thee and the Holy Spirit, one God, for ever and ever.
Celtic Christianity had taken root in Britain and Ireland by the end of the third century. In the fifth century, however, Britain was overrun by non-Christian invaders from northern Europe: the Angles, Saxons, and Jutes.
In 596, Pope Gregory the Great chose Augustine, prior of a monastery at Rome, to head a mission to convert the pagan English. After Gregory consecrated Augustine bishop, the missionary party landed in Kent in 597. The dominant ruler of Anglo-Saxon England was the heathen King Ethelbert of Kent, whose wife Bertha was a Christian princess of the Franks. The king, although initially uninterested in Christianity, allowed Augustine and his companions to live in his territory and freely preach the gospel. Within four years, the king and several thousand of his people had been converted and baptised.