This quotation comes from The Darkening Age: The Christian Destruction of the Classical World by Catherine Nixey, Houghton Mifflin Harcourt, April 2018, 352 pages.

From the Amazon note about the author: “Her mother was a nun, her father was a monk, and she was brought up Catholic.” Not a conventional nun and monk, apparently. And one wonders if their daughter’s discoveries shock them.

Monasteries did preserve a lot of classical knowledge.

But it is far from the whole truth. In fact, this appealing narrative has almost entirely obscured an earlier, less glorious story. For before it preserved, the Church destroyed. In a spasm of destruction never seen before — and one that appalled many non-Christians watching it — during the fourth and fifth centuries, the Christian Church demolished, vandalized and melted down a simply staggering quantity of art. Classical statues were knocked from their plinths, defaced, defiled and torn limb from limb. Temples were razed to their foundations and mutilated. A temple widely considered to be the most magnificent in the entire empire was leveled. Many of the Parthenon sculptures were attacked, faces were mutilated, hands and limbs were hacked off, and gods were decapitated. Some of the finest statues on the whole building were almost certainly smashed off then ground into rubble that was then used to build churches.

Books — which were often stored in temples — suffered terribly. The remains of the greatest library in the ancient world, a library that had once held perhaps 700,000 volumes, were destroyed in this way by Christians. It was over a millennium before any other library would even come close to its holdings. Works by censured philosophers were forbidden and bonfires blazed across the empire as outlawed books went up in flames. 

We will quote more passages from this excellent book.

(Hat-tip Cogito)