What is the historical background that significantly influenced the writtings of the document "Ad Gentes" of the Vatican II council?
The Ad Gentes was a call for spiritual renewal of the Church through a rediscovery of its evangelical mission. It was a response to the sense that many members of the Church were becoming more secular, and that the faith itself was under threat from a modern society that was in many ways turning away from traditional, Church-based religious faiths to either outright secularism or an individual, less traditionally-defined "spirituality." It was a call to focus spiritual energies outward:
Therefore, all sons of the Church should have a lively awareness of their responsibility to the world; they should foster in themselves a truly catholic spirit; they should spend their forces in the work of evangelization.
Through evangelical and charitable activity all over the world, the Ad Gentes argued that the Church could experience spiritual rejuvenation and attract more and more members. So in response to the more secular outlook of many people, the Church did not alter its fundamental teachings, but rather sought to reemphasize what was framed as its original mission.