The spread of Christianity in England was quite a long process. In a short explanation- little by little in the 3rd century Christianity was introduced to Britain. Then Pope Gregory the Great sent a group of Benedictine monks led by St. Augustine of Canterbury to Britain, they conversed with King Ethelburt of Kent in 597 and got permission to speak with his people about Christianity, the king was soon converted to Christianity. Meanwhile, while all this was happening in the south, the Irish were converting people in the north. This process took a few centuries to harden, but in the end it was successful!