Saint Luke is the author of the Gospel according to Christian tradition. According to Luke in the Acts of the Apostles, he was a buddy of Saint Paul the Apostle and the most literary of the New Testament writers. He is commonly thought of being a physician and a Gentile. His actual vocation is unknown but some have speculated that he may have been a member of the Roman military who became a priest after being converted by Saint Paul. Luke is one of the four canonical gospels used by Eastern Orthodox Christians in their services. He is particularly important for Catholics and Protestants alike because his story begins with the birth of Jesus and ends with his death on the cross. Also notable is that he has an account of the empty tomb and the beginning of the Easter season while the other three Gospels do not mention these events. Catholic Church teaching states that "his [Luke's] purpose was to write an orderly account of the life of Jesus Christ, without suppressing anything that might help us understand Him better." He wrote in Greek, a language known as Koine (which means common) because it was the common language of the day. His writings were popular among the early Christians and so many books have been written about him that he has become a saint himself. Some modern scholars believe that Luke was also responsible for writing parts of the book of Acts.