PROVIDENCE, Rhode Island — Sesquicentennial. It’s not a term one often uses in casual conversation, but that is about to change in the Diocese of Providence.

Midway between a centennial and a bicentennial, a sesquicentennial represents a time period spanning 150 years, a milestone quite worthy of major celebration.

Organizers of the Diocese of Providence’s sesquicentennial celebration are planning a nine-month series of events that will engage the faithful on multiple levels, including the celebration of solemn liturgies, presentations by high-profile guest speakers, a variety of concerts, a festival of the arts and the promotion of 150 acts of charity across the diocese to commemorate the milestone anniversary.

Over the course of the celebration, Rhode Island Catholic, the diocesan newspaper, will feature retrospectives on the history of the statewide diocese and each of the eight shepherds who have led it.

Beginning Sept. 8, the feast of the nativity of Mary, and lasting until June 26, 2022, the Diocese of Providence will host an ongoing celebration of the sesquicentennial of its founding in February 1872.

The central theme of the celebration — embossed on the anniversary logo beneath the welcoming outstretched arms of Christ — is rooted in the sacred Scripture of Psalm 126: “The Lord has done great things for us; we are filled with joy.”

Providence Bishop Thomas J. Tobin said he chose this theme because it summarizes very well the diocese’s aspirations for its 150th anniversary.

“On one hand it thanks God for all the gifts and blessings of the past; indeed the Lord has been good to us. And because of that, as we reflect upon that, we are filled with joy as a diocesan church,” Tobin told Rhode Island Catholic.

“But it also gives us a sense — as we express our gratitude for the past — and a reason to go forward to the future in hope and in confidence and in joy. So it combines the elements of the past and the future and that’s what I hope to enkindle through our celebration of our 150th anniversary.”

“A Night to Honor Mary” at 6 p.m. Sept. 8 in the Cathedral of SS. Peter and Paul opens the sesquicentennial. A solemn closing Mass at the cathedral will be celebrated at 1 p.m. June 26 to close the 150th anniversary. That Sunday is the closest to the patronal feast day of SS. Peter and Paul, on June 29.

Archbishop Christophe Pierre, the apostolic nuncio to the U.S. and all of the New England bishops have been invited to the closing Mass.

In the months between the opening and closing celebrations, an extensive, multifaceted program of guest speakers, concerts and artistic events is being planned by the diocese’s 150th anniversary Cultural and Educational Events Committee.

Speakers will include Mike Aquilina, popular author of works on Catholic Church history; Gloria Purvis, host of “The Gloria Purvis Podcast” from America Media; and author and columnist George Weigel. A concert by the world-renowned Vienna Boys Choir and another by the Hillbilly Thomists, a band composed of Dominican friars, have been scheduled.

New York Cardinal Timothy M. Dolan will pay a special visit to the diocese and deliver an address at the cathedral. Other activities being planned throughout the year include a Diocesan Festival of the Arts.

“We’re also developing with our department of Catholic Charities and Social Ministry a program we are calling 150 Acts of Charity in which we will invite our parishes, our schools and organizations to launch new works of charity and justice or to enhance the works of charity and justice that they’re already doing,” Tobin said.

Father Nathan J. Ricci, vice chancellor of the diocese, who is chair of the Cultural and Educational Events Committee, has been developing with Catholic Extension a special calendar highlighting the 150-year history of the Diocese of Providence.

“That’s going to be a very tangible memento of the 150th anniversary of the diocese, but it will also allow us to relive a great deal of our history in various ways,” Tobin said.

Events also are being planned with individual groups and organizations. For example there will be an “Evening with the Permanent Deacons” of the diocese, and a similar gathering for the religious and consecrated men and women ministering in the diocese.

“I hope a lot of the programs that we have ordinarily have will also reflect the anniversary theme — the catechetical programs, social justice programs, seminarian and vocation programs — I hope a lot of the things we do all the time will reflect the theme as well,” he said.

Ricci said the diocese’s 150th anniversary is an important milestone in the life of our local church and provides an opportunity to give thanks to Almighty God for his countless blessings.

“Especially due to Bishop Tobin’s zeal for the diocesan sesquicentennial, we are pleased to host a variety of engaging events throughout the diocese,” Ricci said. “Solemn liturgies, musical ensembles, and inspiring reflections by nationally known speakers will showcase the history and good work of the church in Rhode Island. We hope many Catholics will join us in these important celebrations, almost all of which are free to the public.”

The diocese reached out to the Vatican to obtain a copy of the papal bull promulgated by Pope Pius IX Feb. 16, 1872, to establish the Diocese of Providence. At that time, the First Vatican Council had just concluded and things were still very unsettled in Rome.

The Vatican department involved in the establishment of the diocese at that time was the Propagation of the Faith — the oldest of four Pontifical Mission Societies of the Catholic Church.

“Because we were still mission country at that time,” Tobin said with a smile.

Snizek is executive editor of Rhode Island Catholic, newspaper of the Diocese of Providence.