There is an old axiom from Saint Augustine: “The Blood of Martyrs is the seed of the Christian Church.” In other words, it is the martyrs’ fidelity to Jesus Christ that would prove to be an undying demonstration of loyalty to Him. All through the centuries, the Church thrived under persecution. During the great Roman persecution of the first three centuries, this little sect known as Christians would eventually overturn the mighty Empire. They did so not with weapons or an army but with living a moral life according to the Gospel of Jesus.
In all there were ten great persecutions in the Roman Empire over the course of three hundred years. To be a follower of Christ or even to be sympathetic toward a Christian could mean torture or death. Martyrs were held in great esteem because of their heroic witness. It was this testimony that lead to many conversions. Christianity defended the rights of the poor, the elderly, slaves, women, and children. These sections of society were considered fringes and had no rights. Clergy, wealthy laymen, women who converted to Christianity, and all sorts of support structures in the Church helped to win many to the faith. Paganism was a morally bankrupt religion and did not even offer a hope in the afterlife, and eventually, the old order of paganism was not strong enough to crush the Christians. Christianity in the remaining years of the Empire eventually became the state religion.
Pick any century, and where the Church is persecuted you see a strong and vibrant Christian community. For example, Korea and Africa (mid-nineteenth century), and North America (seventeenth century), all saw a significant growth in the Catholic Church during periods of violent persecution. It was the martyrs’ testimonies of faith and their moral living that won countless souls to Christianity. Even during the persecution of the Catholic Church in Catholic or former Catholic countries— such as Spain during the 1930s revolution, France during the 1790s revolution, and England during the 1570s revolution—the Church remained strong and intact. Ireland’s great witness to its Protestant rulers was that it always remained Catholic. Many of the United States dioceses were headed by Irish bishops, or spiritually taken care of by Irish religious sisters, brothers, or priests. Even in Communist repression, the Church grew strong. Poland and its political-religious movement, Solidarity, overthrew the government. The Polish pope became famous for overturning Communist governments in satellite countries and even in Mother Russia.