I WISH HISTORIANS would not seek to enlarge their subjects. The Reformation was a quite specific and limited phenomenon. It began in 1517, when Martin Luther nailed his ninety-five theses against the trade in indulgences to the door of the Castle Church in Wittenberg, an event some Protestants still celebrate as Reformation Day (31 October). It ended in 1563 with the final session of the Council of Trent, which completed the Catholic religious response, or Counter.:. Reformation. Thus restricted, the Reformation becomes manageable and comprehensible. Confusion arises when it is extended to the next historical phase, the Wars of Religion, which broke out in France in 1562, became Europeanised in the Thirty Years War, and ended with the Peace of Westphalia in 1648. These events were not about reforming the Church but deciding, largely for secular reasons, which parts of Europe would be Protestant, which Catholic.