The Diocese of Worcester announced on Thursday that a Worcester Jesuit middle school may no longer call itself Catholic after continuing to fly Pride and Black Lives Matter flags on its campus.

In his decree, Bishop Robert McManus argued the flags contradict Catholic faith and said the Nativity School of Worcester failed to follow his demands that the flags be taken down. As a result, the school may no longer host Mass or the sacraments on its campus, or sponsor them elsewhere around the Diocese of Worcester.

The Nativity School also cannot conduct fundraisers involving diocesan institutions and must remove former Bishop Daniel P. Reilly’s name from its list of board of trustees.

“As Diocesan Bishop, it is my sacred duty and inherent responsibility to determine when a school claiming to be ‘Catholic’ is acting in such a way that is contrary to the teachings of the Catholic Church and disregards my legitimate authority as the guardian and overseer of Catholic education in the Diocese of Worcester,” McManus wrote in his decree.

Founded in 2003, the Nativity School is an accredited, tuition-free, all-boys school mainly serving students of color from low-income communities. School officials say they’ve kept the flags raised since January 2021 after students called on them to express support making “our communities more just and inclusive.”

In a prepared response to McManus’ decree, Nativity School President Thomas McKenney said the flags will continue to fly while the school appeals the bishop’s decision.

“As a multicultural school, the flags represent the inclusion and respect of all people. These flags simply state that all are welcome at Nativity and this value of inclusion is rooted in Catholic teaching,” McKenney said.

McManus announced in April that the school risked losing its Catholic identity if it continued flying the flags. The bishop argued the Pride flag “stands in contrast” to the idea that sacramental marriage is between a man and woman.

Regarding the Black Lives Matter flag, he said the “Catholic Church teaches that all life is sacred and the Church certainly stands unequivocally behind the phrase ‘black lives matter’ and strongly affirms that all lives matter.” But he argued the Black Lives Matter movement has “co-opted” the phrase, promoting ideas that contradict Catholic faith and seek to disrupt the “family structure.”

McManus did not elaborate on what ideas he was referring to and could not be reached for comment. In an April statement, he said that Black Lives Matter instills distrust in police and those who promote laws.

“The flying of these flags in front of a Catholic school sends a mixed, confusing and scandalous message to the public about the Church’s stance on these important moral and social issues,” McManus said.

But Nativity School officials note that Pope Francis has praised outreach and inclusion of LGBTQ people, and the U.S. Conference of Catholic Bishops supports the spirit and movement of Black Lives Matter. Boston Cardinal Sean O’Malley and the pope have also spoken in favor of the movement.

McKenney said the flags “give visible witness to the school’s solidarity with our students, families, and their communities.”

“Any decisions made by the Diocese will not change the mission, operations or impact of Nativity,” he said.

McManus’ demands that the Nativity School remove the flags have galvanized parts of the Worcester community. In response to the controversy, the Worcester Human Rights Commission raised the Pride flag in front of City Hall. McManus also did not attend the College of Holy Cross’s recent commencement ceremony after students petitioned that he be disinvited.

Other Catholic schools have appealed similar decrees from local bishops, including an Indianapolis Jesuit school that refused to fire a married gay teacher. The appeal ended up reaching the Vatican’s Congregation for Catholic Education, which suspended the decree as it reviews the case.

McManus’ decree is the latest example of him making controversial, conservative decisions throughout his 18 years leading the Worcester Diocese. He has repeatedly expressed transphobic views and criticized LGBTQ rights, including blocking the sale of a diocese-owned Northbridge mansion to a married gay couple.

In 2012, McManus also successfully pushed Anna Maria College in Paxton to rescind its invitation to Victoria Kennedy, the widow of Sen. Ted Kennedy and now a U.S. diplomat, to be its commencement speaker over her pro-choice views.