On January 3, 1941, the “Apostolic Missionary Mission of the Sacred Heart of Jesus”[3] was founded in Mexico City as a separate section of the Diocesan Seminary of Cuernavaca.

On March 25, 1946, a significant step was taken with the establishment of the first novitiate house, in what is called a “foundation in fact”, since the congregation did not yet have formal recognition by the Catholic Church in Rome.

Legionaries consecrate their spiritual and apostolic lives to her care, and seek to take on her virtues of faith, hope, charity, obedience to God, humility, and cooperation with Christ's plan of redemption and justice.

[8] According to the National Catholic Reporter, the Legion or Legionaries of Christ was founded so early in the career of Marcial Maciel, he was ordained as a priest after he was leading the order.

[11] Legionaries have been described as "easy to spot in Rome, young men with close-cropped hair in traditional cassocks or double-breasted blazers, walking two by two like a spiritual army.

It is said to have created "a vast network" of private schools and universities for the children of the elite in that country, which provided funding for his movement’s worldwide expansion.

[13] The Legion presents itself as dedicated to advancing the Church's mission in the world, and to this end claims to submit candidates to a rigorous formation of four dimensions: human, spiritual, intellectual, and apostolic.

Marcial Maciel was born in Cotija, Michoacán on March 10, 1920, into a devout Catholic family—four of his uncles were bishops—during a time in which the Mexican government was fiercely anticlerical.

[20] Maciel was ordained a priest on November 26, 1944, in Mexico City, but had already founded the congregation [6] in 1941, with the support of Francisco González Arias, Bishop of Cuernavaca.

Two years later in 1946, he presented a donation to the Vatican for $10,000, “a huge sum in a city reeling from the war.”[6] Pope John Paul II praised him in lavish ceremonies and called him an "efficacious guide to youth".

Members of the congregation were taught "the Legion message"—that Maciel "had his enemies, but that he was a living saint for his leadership as an evangelist, drawing the church back from liberal abuses of the Second Vatican Council and attracting young men to a strict religious life.

[24] Maciel died in Jacksonville, Florida, on January 30, 2008, aged 87, and was buried in his hometown of Cotija de la Paz, Michoacán, Mexico.

Cardinal Valerio Valeri received reports "from an older seminarian in Mexico City" and the head of the one Legion high school at the time (Cumbres Institute), who were concerned about Maciel's drug use and "overly affectionate behavior with boys".

[27] After years of denial by the Congregation and the Regnum Christi movement and dismissal of accusations made by many former members, an investigation prompted by the Vatican concluded that allegations of sexual abuse of minors by Maciel were true.

On 1 May 2010, the Holy See issued a communique on its year-long investigation of the Legionaries, condemning "system of power" created by Marcial Maciel, that hid "true crimes" and a private life "without scruples or authentic religious sentiment."

[27] As a result of the scandal, Pope Benedict XVI also removed the vow of charity, which required members to maintain secrecy, impermeability, and refrain from criticism of superiors.

[7] The "very serious and objectively immoral acts" of Maciel, which were "confirmed by incontrovertible testimonies", represented "true crimes and manifest a life without scruples or authentic religious sentiment", the Vatican said.

We are committed to transparency about the abuse that has been perpetrated by Legionaries of Christ, to working towards a culture in which all our priests deeply understand the effects of sexual abuse and their role as spiritual fathers dedicated to nourishing God’s people, and to helping those who have been harmed to heal from their wounds.” [41] In early 2009, the Vatican ordered an apostolic visitation of the institutions of the Legionaries of Christ following disclosures of sexual impropriety by Maciel.

[7] Cardinal Velasio De Paolis was delegated to examine the Legionaries' constitutions and conduct a visitation of its lay affiliate Regnum Christi in 2012.

[47] However, Archbishop Rogelio Cabrera López, head of the Episcopal Conference of Mexico, said on December 22, 2019, that the report is "late and incomplete": "How is it possible that the founder committed crimes for 70 years and no one ever said anything?

"[48] 10 years after the Holy See took over the Legion, in an address directed to Legionaries during their General Chapter of 2020 and to the General Assemblies of Regnum Christi held during the same period, Pope Francis recognized the progress made in their renewal saying: "The new Constitutions and the new Statutes are truly 'new,' be it because they reflect a new spirit and a new vision of religious life, consistent with Vatican Council II and the directions of the Holy See, be it because they are the product of a three-year endeavor, in which all your communities were involved and which has led to a change in mentality.

"[40] However, a report emerged around January 2020 alleging that the papal envoy in charge (the by then deceased Cardinal Velasio De Paolis) "refused to punish or even investigate" a case where a Legion priest, who had direct links to the founder, raped "little girls aged 6 to 8 or 9" in front of their classmates at an elite Catholic school in Cancún, Mexico, and noted a "high-level cover-up by superiors who are still in power".

[38] In response, a month later the Legion promised "accountability and transparency" and "vowed to investigate the confirmed cases of past abuse by 33 priests and 71 seminarians".