On 20 October 1870 pope Pius IX adjourned the First Vatican Council, because of the Italian Rissorgimento troops approaching the city of Rome. Given that the Council had only opened less than a year prior, on 8 December 1869, the act was emblematic. The council, as the Catholic Church's protective response against all things new - rationalism, liberalism, naturalism, materialism, and pantheism - was overtaken by history. Given its premature end not all documents prepared were completed and those that were promulgated, became among the most controversial documents in the nineteenth and twentieth-century Catholic Church, strongly defining its relations to other Christian confessions and modernity. Similarly, around one hundred years after the suspension of the First Vatican Council its historical and theological study was overtaken by the event of the Second Vatican Council, known for its rapprochement to the modern world. The history and results of the First Vatican Council were either forgotten or reinterpreted in light of this subsequent council's decisions. In light of the 150th anniversary of this council, the editors and authors of this volume set themselves the goal of re-examining this tradition of historical and theological reception (and forgetting) of the First Vatican Council.