2 Nevertheless, the struggle between good and evil remained in the world as a sad legacy of the original fall. Nor has the ancient tempter ever ceased to deceive mankind with false promises. It is on this account that one convulsion following upon another has marked the passage of the centuries, down to the revolution of our own days. This modern revolution, it may be said, has actually broken out or threatens everywhere, and it exceeds in amplitude and violence anything yet experienced in the preceding persecutions launched against the Church. Entire peoples find themselves in danger of falling back into a barbarism worse than that which oppressed the greater part of the world at the coming of the Redeemer.
Source: Divini Redemptoris (Vatican.va)