The construction of the Christ the King monument was approved in a Portuguese Episcopate conference, held in Fátima on 20 April 1940, as a plea to God to release Portugal from entering World War II. However, the idea had originated earlier on a visit of the Cardinal Patriarch of Lisbon to Rio de Janeiro in 1934, soon after the inauguration of the statue of Christ the Redeemer in 1931.
In 1941 the land which was used to construct the monument was acquired. In 1949 the cornerstone was finally placed on the site, and managed by the Portuguese Episcopate. Construction began in 1949 and took ten years to complete, funded and supported by Apostleship of Prayer members. Yet it was only in 1952 that the first construction started on the site; at that time the foundations of the monument were established by Empresa de Construções OPCA (at the time, at a cost of 3.020 contos).
The inauguration of the complex officially began on 17 May 1959, and continued throughout the 20th century. On the 25th anniversary of the Shrine in 1984, the Chapel of Our Lady of Peace was first inaugurated. A new plan was approved to recondition the grounds of the Shrine (under the direction of Luiz Cunha and Domingos Ávila Gomes) and also to build a Sanctuary, which included a rectory, a chapel, administration and meeting halls and exhibition galleries.
When Pope Paul VI created the Roman Catholic Diocese of Setúbal on 16 July 1975, under the Papal bull Studentes Nos, the Monument of Christ the King and the Seminary of Almada were still under the control of the Patriarchate of Lisbon. In June 1999 the site came under the authority of the Diocese of Setúbal, which immediately started to restore the monument. The municipal authority was responsible for public works, beginning in May 2001 to clean the area and reorganize the public spaces, under technical supervision of the School of Sciences and Technology of the Nova University of Lisbon. Following the restoration projects, the monument was reopened in a solemn ceremony on 1 February 2001. Due to its national importance, the Conference of Bishops determined that funds collected throughout the country on 23 November 2003 would be used for the restoration.
In order to support pilgrimage to the site, in June 2004 new spaces in the Sanctuary building were inaugurated, including a dining room for 150 people and two segregated dormitories. This was followed on 17 May 2005, with the inauguration of a 150-person dining area and 80-person meeting hall, in addition to two segregated dormitories, dining room and kitchen.
Improvements to the monument and sanctuary of Christ the King began in 2006. By 17 May of that year, the Chapel of Our Lady of Peace was inaugurated, under the supervision of architect João de Sousa Araújo. In the following year (17 May 2007), the Pope John XXIII hall was opened, containing eight oil paintings of the same architect, among them images from the encyclical Pax in Terris and a statue of the Angel of Portugal. Similarly, the old high cross from the Sanctuary of Our Lady of Fátima was donated to the Sanctuary of Christ the King, and unveiled on the same day. On 25 November 2005, the newly remodeled main sacristy in the monument’s chapel, that featured the original statue of the monument by sculptor Francisco Franco, was reopened.
On 17 May 2008, the Chapel of the Confidants of the Heart of Jesus, containing valuable reliquaries of Saint Margaret Mary Alacoque, Saint John Eudes, Saint Faustina Kowalska and Blessed Mary of the Divine Heart Droste zu Vischering was opened, along with the Ten Commandments in bronze, which were placed on the main face of the monument.
The inauguration of the Chapel of the Blessed Sacrament (6 January 2009) witnessed the presentation of two paintings related of the revelations made by Saint Margaret Mary Alacoque and another, which was placed above the tabernacle.
Pope Benedict XVI over flew the shrine on the occasion of his apostolic visit to Portugal in May 2010