John Gray always takes things too far, but the basic lesson he takes away from Tom Holland's book Dominion seems absolutely right to me:

Dominion presents a rich and compelling history of Christendom. What makes the book riveting, though, is the devastating demolition job it does on the sacred history of secular humanism. Holland summarises this intellectual folk tale:

"The triumph of the Church had been an abortion of everything that made for a humane and civilised society. Darkness had descended on Europe. For a millennium and more, popes and inquisitors had laboured to snuff out any spark of curiosity, or inquiry, or reason… That nothing in this narrative was true did not prevent it from becoming wildly popular."

It is a tediously familiar mythology that no amount of historical evidence is likely to dislodge. It was Christian bishops and theologians, as Holland points out, who opposed the enslavement of indigenous peoples in Latin America, and Aristotle who was invoked to defend it. Secular liberals will immediately point out that slavery was practised throughout Christendom during much of its history. Of course this is so, but the fact does not alter Holland’s central point. Even if Christianity in power sanctioned all manner of evils, it set a standard of goodness that simply did not exist in the pagan world.

Gray goes on to complain about "Christian intolerance" and the destruction of "Pagan toleration," so in that sense Gray still is caught up in 18th century mythologies.  This isn't to say Christianity (or, even more, Christendom) can be repristinated, but simply that this contrast isn't really plausible, for reasons I'll leave for another post except for saying telegraphically: anyone who thinks the Romans were tolerant is looking in the wrong place for their intolerance.  It was vast, but differently configured than what we assume "intolerance" must be--because it wasn't really about belief, but about (symbolic) behavior.

Furthermore, for all his annoyances (both that he feels and expresses, and those he provokes in me), Gray gets something else right too, namely, that Christianity is not essentially a bridge to liberalism, but only certain kinds of Christainity, in certain kinds of contexts, facing certain kinds of challenges and certain kinds of opponents, can contribute materially and even centrally to the development of something we call "liberalism." 

Again, continuing my several-days' grousing about public intellectual life today, to me the signal-to-noise ratio in Gray's work, the sizzle-to-steak proportion, the hat-to-cattle balance, seems a bit too high on the side we don't want.  There's a bit too much full-throated contempt here for me, at least me in my best moments.  But the core single idea he wants to get across is in line with a lot of thinkers, from Nietzsche through Charles Taylor and Talal Asad: The world we live in remains thoroughly "path dependent" on its Christian energies.  Not exclusively, of course, nor is this a triumphalist claim.  It is, however, a fundamental claim, in the sense that interesting and illuminating investigations about our world, its past, and its future all can commence from a recognition like the one Holland propounds in this work, and Gray in his review.