The Council

The First Vatican Council (1869-1870) had been adjourned after the capture of Rome by Italy, leaving open a number of questions, especially those concerning pastoral theology or the role of the Church. In the 1920s, there is talk of resuming the council, but unrest in Europe, and soon after, the Second World War, prevents it.
Shortly after his election, John XXIII (1958-1963) announces plans to convene an ecumenical council. His aim isn’t to complete the adjourned council, rather it‘s to enable the Catholic Church to adjust its message to in so that it reaches a rapidly changing world: the doctrine of the Church is unalterable, but it needs to be presented in a manner suited to these new times, an idea that is summarized by the term aggiornamento (bringing up to date). Nevertheless, several factions wish to use this opportunity as a way to modernise the Catholic Church by better including the laity, for example by involving them in the liturgy, by studying the Bible and the Church Fathers in a more scientific manner, thus reinventing it, by being open to other Christian denominations. But other factions fear that concessions to the modern world are a danger to the integrity of the faith. They worry about secularisation, about the diminishing status of Catholicism, and about the influence of the “modern errors”. They also reject ecumenism since they see it as a vector for relativism. Over 2,000 council fathers (bishops and superiors of religious orders) take part in the council, which runs from 11th October 1962 to 8th December 1965. They start by rejecting the program and the texts prepared by the Roman Curia.
The Council covers a range of topics. The Lumen gentium constitution (21th November 1964) deeply changes the structure of the Church. The bishop figure gains importance: it’s not a cog in the wheel of the Church anymore, but a central figure. The collegial character of the task results in the creation of episcopal conferences which gather all bishops of a given country.
The Sacrosanctum concilium constitution (4th 1963) alters the liturgy. Until then, the faithful read in silence the prayers spoken by the celebrant: now they interact more with the priest, who is facing them. To be more understandable, the liturgy has to place greater emphasis on vernacular languages which, after a while, led to the near extinction of Latin.
The Gaudium et spes constitution (7th December 1965) deals with the relationship between the Church and the world. It puts an ends to the mistrust that ruled until then, preferring to stress the contributions that Catholicism can make to matters such as social justice, family, culture, or politics. The Dignitatis humanae declaration (7th December 1965) is one of the most controversial texts. It demands the free exercise of religion in society and condemns any attempt to impose a faith on other people. This declaration is a breakthrough, because before it the Catholic Church requested religious freedom solely for its followers, even if this meant restricting it for others when Catholicism was the main religion. Now, the Catholic Church presents itself as a defender of freedom of worship for all religions.

Ecumenism and interreligious dialogue

In line with this affirmation of religious freedom, Vatican II commits to ecumenism and interreligious dialogue, which are two distinct but sometimes mistakenly interchanged phenomena. Indeed, ecumenism aims to unify the different Christian denominations, while interreligious dialogue strives to develop exchange and mutual understanding between Christianity and other religions. This too constitutes a major reorientation.
Ecumenism was born in the mid-19th century from efforts to bring the many Protestant denominations closer together. At the same time, a dialogue between the Orthodox and Anglican Churches is starting. The Ecumenical Council of Churches is created in 1948: it doesn't aim to become a "super-church", but to push the various Christian denominations into meeting and discussing one another . Until 1961, the papacy had forbidden Catholics to take part in it, and even since then, the Catholic Church only ever had observer status.
In 1940, Roger Schütz (future pastor) decides to put into practice this ecumenical ideal by founding a community in Taizé (France). His objective is to gather brothers from all walks of Christianity to settle into a monastic type of community with ecumenical vocation.
At first, the Catholic Church was against ecumenism. It stays true to the traditional view of Christian Unity through the return of the “Christians in the wrong” into the Roman fold. In the Mortalium animos encyclical (1928), Pius XI (1922-1939) condemns the efforts of those wishing to regroup all Christian churches: this unity must only be achieved by the dissidents’ return in the one true Church - the Catholic Church.
Catholic officials, however, have been working toward Christian Unity prior to Vatican II. In 1926, Lambert Beauduin founded founds established a monastic community which is striving for Christian unity and settles 1939 in Chevetogne (Belgium). What makes this monastery unique is that comprises two liturgical groups: one following the Roman rite, and one following the Orthodox rite. Another pioneer of Catholic ecumenism is Dominican Yves Congar who publishes in1937 Divided Christendom : a Catholic Study of the Problem of Reunion, which caused him to be treated with suspicion by Rome: the Humani generis encyclical (1950) condemns his ideas.
The Unitatis redintegratio Decree (21st November 1964) therefore constitutes a complete change in perspective. Christian unity becomes an objective goal of the Catholic Church, shaping ecumenism into an essential aspect of Christian life. This time, the objective is no longer the conversion of other Christian denominations to Roman faith, but the unity of these Churches as a whole. This implies acknowledging them and understanding them better without sacrificing the Catholic Church's unique place of the Catholic Church.
The Nostra aetate declaration (October 28, 1965) also opens the dialogue with non-Christian religions. By stating that God is everywhere and that he is also active in non-Christian religions, this declaration allows the establishment of relations based on dialogue and better mutual understanding, although it points out that Christians are still required to proclaim Christ. Relations with Judaism are turned upside down: Nostra aetate condemns the persecution that Jews have been subjected to, rejects the idea of a "deicidal people" (the phrase "perfidious Jews" used in the liturgy can have supported this idea), and emphasizes the Jewish origin of Christianity.

Post Council era

Vatican II is fairly quickly faced with diametrically opposed criticism. Some criticize the council for letting go of tradition and disregarding papal condemnations issued during the nineteenth century. Traditionalists find their spokesperson in archbishop Marcel Lefebvre, who in 1970 founds the Society of Saint Pius X. He had attended Vatican II, during which he had expressed how opposed he was to religious freedom and ecumenism, but he had signed the Council's declarations nonetheless. He rejects them in 1974. The dialogue is maintained at first, before archbishop Lefebvre and the four bishops he had ordained — despite the pope having forbidden him to do so — are excommunicated in 1988. Discussions concerning the return of this community into the Roman fold are still underway.
Conversely, the so called Catholic “reformers” or “progressive” Catholics are disappointed that the Church didn’t truly complete the modernization efforts initiated by the Council, be it on the matter of the priests' lifestyle or of the women’s role in the Church. They feel that the Council was not really put into practice except with regard to the revision of the liturgy. They consider that, in terms of moral or ecclesiology, the conservatism practiced during John Paul II (1978-2005) and Benedict XVI's (2005-2013) pontificates betrays the spirit of the Council.