The Pope lived in Rome. He was in charge of all the bishops and priests around the World. He read the Bible and told people what to believe. A British priest named Pelagius read the Bible and decided that what the Pope told people was wrong. He told people to believe slightly different things. His type of Christianity was called 'Pelagianism'. The Pope became worried when Pelagianism became popular in Britain. He thought everyone should do as he told them. People who didn't were called 'heretics'. You could be punished for being a heretic. This was difficult to do though, because Britain was a long way from Rome. The Pope sent St. Germanus to Britain to sort things out. He was the Bishop of Auxerre in Gaul (now called France). St. Germanus visited Britain in AD 429 and again in AD 447. He went round the country persuading people that Pelagianism was bad. He also visited King Vortigern. Before he became a bishop, St. Germanus had been a soldier. While he was in Britain, he organised the British army and helped King Cadell of Powys by winning a big battle against the Saxons and the Irish. This made Germanus very popular and so people stopped listening to Pelagius.