When Bishops Meet
By John W O’Malley
Harvard University Press, 223pp, £20/$24.95

How many bishops does it take to change the course of Catholic history? The answer, as John O’Malley’s spirited new book explains, can vary.

Attendance rates during the early sessions of the Council of Trent were pitiful: somewhere in the region of five per cent of the invited delegates turned up. Four hundred years later, the picture was very different. Ninety per cent of the world’s episcopate – that’s 2,400 or so bishops – took their seats at the opening sessions of Vatican II.