I’ve been reading about Jan Kupecky, a Baroque Bohemian portraitist, whose paintings I fell in love with in Prague several years ago. (This lousy reproduction does not begin to convey the extraordinarily modern irony and chiseled delicacy of this sitter’s expression (he is the miniaturist painter Carlo Bruni); the lips of this young tutor blaze mesmerizingly red in the original.) Kupecky’s family history in what is now the Czech Republic is a reminder of what Christianity meant when it was at the height of its power and in league with the state. The first throes of the Thirty Years War began in Bohemia, from which Protestants were driven out unless they agreed to convert to Catholicism. Starting in 1627, one fourth of the nobility and one fifth of the burghers, including Kupecky’s parents, emigrated. From the middle of the 17th century, non-Catholicism was considered an offense against the Habsburg state in Bohemia. Such worldly power plays were as much the natural condition of Christianity as its more recent tamed American version.