The transformational missive came from the Roman Catholic bishops at the end of the Second Vatican Council in 1965.

Nostra Aetate (Latin for "In Our Time") decreed that the church would lay down centuries of blame and recrimination toward the Jews and respect their faith as one that has an enduring covenant with God.

St. Joseph's University heeded the call, organizing a two-day conference two years later featuring Msgr. George G. Higgins and Rabbi Marc H. Tanenbaum, a priest and a rabbi with integral roles in the development of the church's new vision.

Decades later, that pioneering step has evolved into an abiding commitment: the St. Joseph's University Institute for Jewish-Catholic Relations, which is celebrating its 50th anniversary on Sunday.

The institute, founded with the cooperation of the American Jewish Committee and the aid of the Archdiocese of Philadelphia, serves as a center of scholarly research, offers college courses on Jewish-Christian relations, and sponsors interreligious dialogue and community outreach.

"After moving away from hatred, the task is [now] more sophisticated," said Adam Gregerman, the institute's assistant director and an assistant professor of Jewish studies at St. Joseph's. "What does it mean for two different traditions to claim to be in covenant with God and share a holy book? Those questions are more profound than dispelling stereotypes."

Gregerman and institute director Philip A. Cunningham are guiding the center as it considers those issues during a troubling wave of religious intolerance that has erupted in violence, harassment, and the desecration of houses of worship.

The scholars view those incidents as moments of scapegoating and fear that arise during times of polarization. The more lasting lesson is the support for victims of intolerance that almost uniformly – and quickly – emerges from diverse communities.

"That's proof of progress," said Cunningham, a professor of theology specializing in Christian-Jewish relations.

Now guided by two full-time faculty members, the institute in its nascence was led by the Rev. Donald G. Clifford. He and interfaith activist Charles Kahn Jr. of Rydal, a board member of the American Jewish Committee in Philadelphia, organized annual panel discussions, outreach efforts, and trips to Israel and Rome to foster understanding between the communities. Clifford retired in 2008, and Cunningham succeeded him. Clifford died in 2009. Kahn, 92, is still active in interfaith efforts.

In 2015, the institute unveiled Synagoga and Ecclesia in Our Time at the campus' Chapel of St. Joseph. The sculpture, whose two female figures symbolize the church and the synagogue, was blessed by Pope Francis when he visited Philadelphia that year.

The institute's  anniversary celebration, called "A Genuine Gift of God," will re-create the first conference on March 5, 1967, when Higgins and Tanenbaum made their presentations at what was then Campion Hall.

During Vatican II, Higgins, then social action director for the U.S. Conference of Catholic Bishops, served as a consultant to the ecumenical council. Tanenbaum, director of interreligious affairs for the American Jewish Committee, helped in the drafting of Nostra Aetate.

The anniversary celebration will feature presentations by the Rev. Dennis McManus,  a consultant for Jewish affairs with the bishops' conference,  and Rabbi A. James Rudin, senior interreligious adviser for the Jewish committee. They will discuss the deepening relationship between the faith traditions, reflect on the past, and consider the future.

Two ancient faith communities "living side by side throughout history, and only in the last 50 years has really significant and permanent change begun. ...," Rudin said. "If Catholics and Jews can start on a path to mutual respect and understanding, that should be a model for other groups that have a rocky history."

 "A Genuine Gift of God: Celebrating 50 Years of Catholic-Jewish Dialogue in the United States," from 7 to 9 p.m. Sunday, Haub Executive Center, McShain Hall, St. Joseph’s University, 5600 City Ave.  Free. For more information, visit the website of the Institute for Jewish-Catholic Relations.