In a letter dated June 10 and addressed to leaders of the worldwide order, Fra' Giacomo Dalla Torre said it was his duty to ensure the communion that unites all members of their religious family "is present in every aspect of our order's life."
"Among all the elements which constitute out spiritual life, the question of the liturgy to use in our celebrations has a particular significance," he wrote.
When Pope Benedict XVI eased restrictions on use of the 1962 Roman Missal, known as the Tridentine rite, in 2007, the papal instruction permitted the major superior to decide the matter for religious institutes or societies.
"I have thus decided, as supreme guarantor of the cohesion and communion of the order ... that henceforth all the liturgical ceremonies within our order must be performed according to the ordinary rite of the church -- rite of St. Paul VI -- and not the extraordinary rite -- Tridentine rite," Fra' Dalla Torre wrote.
He asked that all members, chaplains and volunteers be informed of the decision and ensure that the decision be "immediately put into practice" and respected.
Despite the way the letter was worded, the letter was meant to reaffirm existing guidelines of the order, and was not an announcement of a new decision, Marianna Balfour, the order's diplomatic public affairs and press officer, told Catholic News Service June 11.
"The grand master issued the letter, containing no novelty, aimed only at fostering unity in the order," she wrote in a series of email responses to questions.
The letter does not intend to interfere with members' personal preferences as "each member has his or her own right to participate in any celebration preferred," she wrote. The letter refers only to official celebrations of the Order of Malta.
"The letter was intentionally issued to put an end to any form of discrepancy regarding liturgical celebrations. The Order of Malta has 13,500 members worldwide and is present in 120 countries," she said. "As its religious superior, the Grand Master is responsible for encouraging uniformity and cohesion."
The letter came after the order's general chapter in May as the grand master has been leading efforts to reform the order.
It has been grappling with a number of internal disputes, one of which led to the resignation of Fra' Matthew Festing as the order's grand master in 2017 at the behest of Pope Francis. The pope had established a commission to investigate Fra' Festing's removal of the order's grand chancellor, Albrecht Freiherr von Boeselager, who was later reinstated as grand chancellor.
In an annual address to diplomats in January, Fra' Dalla Torre said the reform of the order's constitutional charter "has led to the definition of some key themes for the order's life, and in particular, its religious members."
Some aspects of the reform had been agreed on, he said, "including the importance of a spiritual life, which for a Catholic order must remain a guiding inspiration."
The lay Catholic religious order provides medical care to the poor, the elderly and those with disabilities, offers humanitarian relief following disasters and assists migrants and refugees.
Several dozen male members make a profession of poverty, chastity and obedience, lay knights and dames promise obedience and the vast majority of members make a commitment to the mission of the order's charitable activities.