December 2015 marks the 50th anniversary of the most controversial document of the Second Vatican Council, the 'Declaration on Religious Freedom', Dignitatis Humanae. Ever since its promulgation, it has been the subject of prolonged and often impassioned debate. What precisely does it teach? What is its authority? How can it be reconciled with the Church's teaching about the kingship of Christ and the duties of Catholic statesmen? Scholars from all over the world will be meeting in Norcia this autumn, in the presence of Cardinal Raymund Burke, to discuss these vital questions.