On religion and secularity, or why the middle ages were better

I'm presently reading through Professor Eamon Duffy's concise book, Ten Popes Who Shook the World.  This afternoon I found these words in his chapter on Pope Gregory VII particularly apt:

For a hundred years or more, most western countries have worked on the axiom that our common life together ought to be deliberately secular.  Religion in a free society may be acceptable as a private activity, like knitting or going to the gym, but it has no proper place in the spheres of politics, economics or citizenship.

The rise of militant Islam, like the influence of the Christian Right on American foreign policy and, perhaps more encouragingly, the role of the Catholic Church in the overthrow of Polish communism, might suggest that in the real world things are not necessarily quite so simple.

That much at any rate was understood in the Middle Ages, where everyone accepted that religion - the fundamental understanding of life, death, the Universe and everything - was liable to have an impact on the way that society was organized (60).

This is a helpful book that offers short synopses of the most important activities of a few of the Popes.  There is, though, one error in the book.  Duffy, in his chapter on Saint Peter, says: "...the long line of bishops of Rome, the popes - all 262 of them - are Peter's successors" (30).  Pope Benedict XVI is the 265th Successor of Peter, making him the 266th Pope.