Petrus, also known as Peter, was one of the twelve apostles of Jesus Christ. He is often considered the leader of the apostles and played a significant role in the early Christian church. Petrus was originally a fisherman and was called by Jesus to follow him, becoming a key figure in spreading the teachings of Christianity. Petrus is traditionally recognized as the first pope of the Roman Catholic Church. He is often depicted in art holding keys, symbolizing his role in the "keys to the kingdom of heaven." His life and teachings are documented in the New Testament, particularly in the books of Matthew, Mark, and Acts.