How to preach to the unconverted

In the late 20th century, Reformation studies shifted away from being a branch of historical theology towards a subject, and a problem, in social-cum-cultural history. It is no longer as relevant to determine what Luther or Calvin had to say as to understand what they were heard to be saying. It is also insufficient to regard ordinary people as passive recipients of new ideas. The Reformation was a multiple agency and a complex interaction. Historians of the Reformation in England, where this revolution was mostly involuntary, confront the riddle of compliance. In the freer market of religious contention that was Luther's Germany, and in the polarised religious climate that followed, we need to understand by what means people were converted to Protestantism and consolidated in membership of Protestant churches.

There is no one better qualified to provide an overview of where we now stand than Andrew Pettegree, who from the Reformation Studies Institute at St Andrews University surveys the newest work in the field. He is an authority on the formation of Calvinist communities and on the dynamic role of the book trade in the various reformations that changed the face of Europe. The instrumentalities employed in what he calls the culture of persuasion are familiar: preaching, music, stage plays, visual images, print. But Pettegree has new things to say on all of them.

It is right to give priority to preaching. But to read a sermon, as printed, is not to know how it worked as preached: "It is extremely difficult to reconstruct the sermon as event." Historians have been tone-deaf, and the most neglected of the converting, consolidating media has been music. Lutheran hymns and Calvinist psalms were about communal participation as well as protest, as in Luther's Ein' feste Burg, "the Marseillaise of the Reformation".

Pettegree's chapter on the visual image contains important criticism of the most influential discussion of its impact in Luther's Reformation, the late Robert Scribner's For the Sake of Simple Folk . Pettegree is at his best in his account of print and the book trade, grounded in knowledge of the economics and organisation of the industry.

These studies take us about as far as we can get towards understanding how Protestants were made, but inevitably not all the way. Historians cannot dissect minds and consciences, and can only see in a glass darkly.

Patrick Collinson is emeritus regius professor of modern history, Cambridge University.