Vatican II was one of the most significant events in the life of the modern Church. Between October 1962 and December 1965 the largest ever gathering of Catholic bishops answered the call of Pope John XXIII to let some fresh air into the Church. Completing the work of an earlier Vatican Council that had been cut short, and in a tradition of ecumenical councils dating back to the time of the Apostles, Vatican II laid the foundations for a renewal process that still continues.

Gaudium et Spes (the Pastoral Constitution on the Church in the Modern World) instructs the faithful on the importance of Christian engagement with the world and the principles that should govern that engagement today. It is a document of particular importance to the laity, whose responsibility it is to transform the society in which they live. Pope John Paul II took two of the document's themes - that of the importance of culture, and that of a new understanding of human nature centred on Christ - and made these fundamental to his pontificate.