The Roman Catholic Church is part of the Christian Church ruled by the Bishop of Rome (the Pope). In the early Church the papacy exercised authority over all Christians. In about 575 a monk called Gregory saw some young men in the Rome slave-market. He spoke to them and discovered that these men were from England. After talking to these slaves he was shocked to discover that there were very few Christians living in England. Gregory was determined to change this situation and when he became Pope he sent his friend Augustine and forty monks to England to convert the inhabitants to Christianity.