The biomedical devastation [of the Black Death] had a strange and complex impact on the Church. It may have reinforced a trend away from optimism to pessimism, from a God who could be partly encapsulated in reason and was a mighty comfort and fortress, to one whose majesty and planning and rationale were impenetrable, although that pessimistic inclination was already rising in intellectual circles thirty years before the Great Pestilence.SOURCE: In the Wake of the Plague: The Black Death & the World It Made, by Norman F. Cantor (Harper Perennial, 2002), pp. 203-206
The century after the Black Death was marked--in England, France, the Low Countries, and Germany--by what may be called the privatization of medieval Christianity. This took both organizational and spiritual forms. Organizationally there was a rush by the affluent upper middle class to found chantries, private chapels supported by one family or a small group of families. The great lords and millionaire gentry and merchants had always had private chapels. Along with the capability of having three hundred people for dinner in your household, it was the signal conspicuous consumption of great wealth.
In the more plebeian chantries, the rising middle class imitated their betters. Even the workers organized into craft guilds got into the act. The labor corporations also became confraternities that sustained private chapels and provided burial benefits to their members.
Spiritually and intellectually, the century after the Black Death in England and elsewhere in northern Europe was marked by the rise of intense personal mysticism and separately by a privatist kind of bourgeois behavior in elaborate spiritual exercises....
The Black Death provided an activating psychological context for privatization of late medieval religions. It did not create it.
UPDATE: Up-and-coming medievalist Andrew Reeves comments:
I disagree with this assessment that the plague had much to do with an increased sense of individualized devotion. The real period for "privatization" was the thirteenth century. It was the Church's emphasis on genuine penance and contrition in the area of sin that began in the twelfth century and reached it's full articulation in Lateran IV that began it.Maybe that accounts for Cantor's waffling a bit in the final paragraph of the excerpt quoted above.
Now then, the profusion of pastoralia (manuals of pastoral care, dealing with confession and instruction) in the years around Lateran IV and after was most extensive in England and France north of the Loire, but such materials appear in other parts of Europe as well.