The New Testament Christian Church faced many obstacles in the era of its origin and spread in Europe. At the same time, according to Tucker, one of its main differences from other religious doctrines was that it was based not on mythology and customs but on facts. Individual adherents of Christianity made a significant contribution to the spread of evangelical ideas and rooted missionary traditions that were adopted by new generations in the future.
Initially, missionaries did not have crucial difficulties, but later, resistance to evangelical ideas from pagans led to persecution and threat to the lives of those who confessed their faith in public. Tucker focuses on several individuals who made colossal contributions to the advancement of Christianity and went down in history as martyrs who gave their lives for personal convictions. Among them, one should note the apostle Paul, the bishops Polycarp and Ulfilas, the martyrs Perpetua and Felicitas, and the missionaries Patrick and Columba. The merit of these people lies in following Christian values and laying the foundations of missionary work as a movement to spread the religion in the territory of modern Europe.
The Gospel also crossed borders due to individual monarchs who acted as supporters of Christianity and spread the religion within their domains. Tucker mentions Charlemagne as one of the illustrious rulers and adherents of Christianity. The Celtic conquests were the result of the Christianization of many barbarians, and the emergence of the Jesuit and Dominican orders became the driver of the spread of this religion on a global scale. Thus, due to active educational work, Christianity turned into one of the main world religions.