St. Augustine of Canterbury (from the website: catholicexchange.com)
The sixth-century bishop St. Augustine of Canterbury (d. 605) is famous for his missionary work in England (not to be confused with St. Augustine of Hippo, the great Church thinker of the fourth century). Augustine was the prior or abbot of a monastery in Rome. In 596 the Pope, St. Gregory the Great, chose him to lead a group of thirty monks on a missionary journey to England (there were some scattered Christian communities there, but the land as a whole was still predominantly Anglo-Saxon and pagan).
Augustine’s group set out, but on reaching France, heard terrifying stories of the treacherous waters of the English Channel and the ferocious temperament of the Anglo-Saxons. Augustine hurried back to confer with the pope, but Gregory reassured him that his fears were groundless, and sent him back on his way.
The missionaries arrived in England in 597. King Ethelbert, a pagan married to a Christian, received them kindly, and their work flourished. On Pentecost Sunday the king was baptised, along with many of his subjects. Augustine journeyed briefly to France, where he was consecrated a bishop, and then returned to England, establishing his see, or diocese, in Canterbury. The see at Canterbury continued to prosper, and additional dioceses were later established at London and Rochester.
Not all of Augustine’s efforts were successful; his attempts to reconcile the Anglo-Saxon converts and the original Christian inhabitants of England failed, and for a time the missionaries’ work progressed slowly. By the time of St. Augustine’s death in 605, however, a solid foundation for England’s later widespread conversion to Christianity had been established.

For a more complete biography see also: http://www.newadvent.org/cathen/02081a.htm