According to Roman Catholic teaching, the Roman Catholic Church began when Jesus named Simon Peter the first Pope as told in Matthew 16:18. In this New Testament passage, Jesus describes how he would build a church with Simon Peter serving as the rock of the Church. Although no institutionalized or centralized church existed at this time, Catholics throughout the world believe that the Roman Catholic Church was created at this moment.
Following Jesus's death, Simon Peter and the apostles began to proselytize followers throughout the Mediterranean region. This expansion was aided by the infrastructure of the Roman Empire, which helped spread new ideas such as Christianity. The first Christians were not very organized, followed many Jewish traditions and continued to worship alongside Jewish groups. Gradually, however, groups of Christians began to develop their own practices, and by the year 100, regional bishops led local groups of Christians, while the Bishop of Rome settled disputes between groups.
As of 2015, the Bishop of Rome, more commonly known as the Pope, still serves as the leader of the Roman Catholic Church and resides in Vatican City. Constantine gave the Roman Catholic Church the land that is now known as Vatican City in the year 313. Vatican City serves as the headquarters for the Roman Catholic Church. Vatican City was given its independence from Italy in 1929. As of 2015, experts estimate that there are over 1.2 billion Roman Catholics in the world.