During the first few decades of its history, Christianity grew by leaps and bounds and, as far as we can ascertain, its first devotees worshiped openly, constructing their own churches for the purpose. The first Christian missionaries, including the apostles, exploited the open borders created by Roman administration and traveled far and wide across the vast sweep of the empire, attracting converts everywhere they went. To be sure, they were sometimes resisted by votaries of local deities who correctly perceived in Christianity a potent new rival, but the Romans themselves, with the latitude typical of polytheism, seem to have regarded Christianity as just another oddball sect of the sort that proliferated in such a sprawling and culturally diverse empire.
All of that changed, however, on July 19, 64 A.D. Sometime late at night on the 18th or very early on the 19th, a fire broke out near the Circus...
The author incorrectly assumes that Catholics and Eastern Orthodox were Christians. Most of the fiercest persecution (see Foxe's Book of Martyrs) where done by the Catholic Church, the same ones that the author terms as Christians.
"If Western civilization were assigned a starting date, Christmas Day in the year 800 would be a very good choice. On that day, the ambitious Frankish monarch Charlemagne, who had recently restored Pope Leo III to his seat at the Vatican from where he had been driven by would-be assassins, attended mass at St. Peter‚Äôs Basilica. To the astonishment of the assembled multitude, the pope interrupted the service to place a crown on Charlemagne‚Äôs head, and declared him emperor over a restored Western Roman Empire. What came to be called the Holy Roman Empire was the first great power to emerge in the new Western Christian civilization; it was an attempt to recreate the glory of the realm of the Caesars, but in a Christian, rather than a pagan, setting."