Paul the Apostle, commonly known as Saint Paul, and also known by his native name Saul of Tarsus, In the mid-30s to the mid-50s AD, he founded several churches in Asia Minor and Europe. Paul took advantage of his status as both a Jew and a Roman citizen to minister to both Jewish and Roman audiences. According to writings in the New Testament, prior to his conversion, Paul was dedicated to persecuting the early disciples of Jesus in the area of Jerusalem. Approximately half of the book of Acts deals with Pauls life and works. Fourteen of the twenty-seven books in the New Testament have traditionally been attributed to Paul. Seven of the epistles are undisputed by scholars as being authentic, with varying degrees of argument about the remainder. Pauline authorship of the Epistle to the Hebrews is not asserted in the Epistle itself and was already doubted in the 2nd and 3rd centuries. Today, Pauls epistles continue to be vital roots of the theology, worship, and pastoral life in the Catholic and Protestant traditions of the West, and the Orthodox traditions of the East. Augustine of Hippo developed Pauls idea that salvation is based on faith and not "works of the law". Martin Luthers interpretation of Pauls writings influenced Luthers doctrine of sola fide.