The Mass began with a procession by 34 of the national communities of the archdiocese, most in their traditional dress and carrying the flag of their nation, which they posted on the left-hand side of the altar.

In addition to the more than 150 priests, the cardinal was joined by concelebrants Cardinal Justin F. Rigali of Philadelphia, Archbishop Alfred C. Hughes of New Orleans and a former auxiliary bishop of Boston, as well as more than 20 bishops from New England and around the country.

“I am pleased to join with Cardinal O’Malley and the people of the Archdiocese of Boston for this important and prayerful moment in their history,” said Cardinal Rigali, whose mother was born and raised in Boston.

“As brothers and sisters in Christ, the faithful of the Archdiocese of Philadelphia join with the Catholic community of Boston in celebration of our bicentennials recognizing God’s sustaining presence in our parishes, schools, and social service ministries,” said the cardinal, whose own archdiocese shares it bicentennial with Boston. “We pray that God continues to bless the Archdiocese of Boston with His loving grace.”

The leader of Boston’s Melkite Catholic community, the Eparchy of Newton Cyril S. Bustros, who joined Cardinal O’Malley on the altar, said he was honored to participate in the closing Mass.

The archdiocese’s diversity was again expressed during the General Intercessions, which were proclaimed in Portuguese, Cape Verdean Creole, Haitian Creole, American Sign Language, Korean, Igbo-Nigerian, Irish and English.

The Mass’s music program was one more tribute to the Church in Boston’s rich ethnic mosaic with different parts of the service accompanied by the Cathedral Festival Choir, made up of singers from several parishes, the Archdiocesan Black Catholic Choir, the Cathedral Brass Ensemble and choirs from the Chinese, Ugandan and Indian communities.

The cardinal inaugurated the Cherverus Medal, a sterling silver medallion with the likeness and coat of arms of Bishop Jean-Louis Cheverus, the city’s first bishop, which he presented to 68 individuals after Communion.

The medal was awarded to individuals who have demonstrated outstanding Christian leadership and service at parishes, agencies and schools in the archdiocese.

In his blessing of the medals, the cardinal said, “I am privileged to have the opportunity today to honor these men and women, whose selfless dedication and commitment has greatly contributed to our carrying out our mission given to us by Jesus Christ.”

As Father Kevin J. O’Leary, the cathedral’s rector, read the list of names, the cardinal approached each recipient, who stood forming a half-circle in front of the altar, and placed the medal with a red sash around their necks.

Deacon Leo J. Donoghue, who assisted the cardinal during the Mass along with Deacons Anthony P. Rizzuto and Charles I. Clough, said his being with the cardinal as he presented the medals gave him a unique perspective.

“It was not supposed to be a spiritual experience, but it was a spiritual experience for me,” he said.

Deacon Donoghue said he could see the reactions on the faces of the recipients as the cardinal presented them with their medal. Some were smiling, some were crying and some had a look of disbelief, he said.

John R. Manuel, who was recognized for work organizing the Filipino Apostolate 12 years ago, said he was surprised when he opened the letter two weeks ago from the cardinal telling him he was receiving the medal.

“I am so proud of him, especially because this is the first time the award has been given,” said Manuel’s wife Belinda.

Meyer Chambers said he was humbled to receive the medal. “Why me? I was standing there in the presence of so many people who have done so much more for the Church than I have.”

Chambers, who is the director of the Boston Black Catholic Choir and is the former director of the Office of Black Catholics, said at a choir rehearsal he called the singers together to tell them that he was selected, but he sees the award as one he received on behalf of all of them.

Another recipient, Brother James Curran, the founder of the Little Brothers of St. Francis said during the Mass he was thinking about the late Cardinal Humberto S. Medeiros, who was the order’s founding bishop and Cardinal William H. O’Connell.

It was for the funeral of Cardinal O’Connell that Brother James made his first visit to the cathedral in 1944, two months after his father, a tailgunner, was shot down over Munich.

Before the Mass ended, the cardinal delivered an Apostolic Blessing. Deacon Donoghue made the proclamation for the congregants to prepare for the blessing, which the cardinal proclaimed in Latin.

The blessing included a plenary indulgence, which grants remission of temporal punishment for sins.

After the Mass, the cardinal hosted a modest reception at the Cathedral High School gymnasium across the street, where he was joined by several of the priests and bishops.

“We have witnessed a great expression of our Catholic faith during the past year,” said Father Robert L. Connors, the director of the Bicentennial Planning Committee and pastor of Dracut’s Saint Marguerite d’Youville and Saint Francis of Assisi Parish.

“As we go forward as an archdiocese we can look back with great joy at what we have accomplished and what blessings are in front of us, reminded of course, that we continue to Journey Together in Christ,” he said.