On 31 October 1517, as every child once knew, an obscure German monk nailed his 95 theses to the door of Wittenberg’s castle church and so began the Reformation. It would seem that there is no firm evidence that this ever actually happened as myth would have it, but whether Martin Luther nailed his theses to the door or glued them or merely posted them to Germany’s leading churchmen, the Christian world would never be the same again.