BOSTON — Cardinal Seán P. O’Malley will be joined by a delegation led by His Eminence Methodios, Metropolitan of the Greek Orthodox Diocese of Boston and All New England for vespers June 29, the Feast of Sts. Peter and Paul, patron saints of the Church of Rome.

The public is invited to attend the celebration, which will be held at 7 p.m. in the Blessed Sacrament Chapel of the Cathedral of the Holy Cross.

During the 1960s it became a tradition for the ecumenical patriarch of Constantinople to send a delegation to Rome on the Feast of Sts. Peter and Paul, and the local celebration in Boston has always been important as a way of “bringing to life the examples of the hierarchs,” said Vito Nicastro, associate director of the Office for Ecumenical and Interreligious Affairs for the Boston Archdiocese.

“Ever since the joint pilgrimage of Bostonian Catholics and Orthodox in 1996 to Rome and Constantinople, it has become a tradition here as well for the archdiocese to invite the Eastern Orthodox to join us for the Feast of Sts. Peter and Paul,” he said.

According to Nicastro, it is the 10th anniversary of the exchange and “our two Churches are preparing a new pilgrimage to Rome and Constantinople like the one which kindled the exchange in 1996.”

In Rome, Pope Benedict will preside at the Feast of Sts. Peter and Paul June 29 and will travel to Constantinople Nov. 29 to greet the ecumenical patriarch and celebrate the Feast of St. Andrew, patron saint of the patriarchate.

“The Holy Father has dedicated himself to the effort to build Christian unity, which was one of the ‘principle concerns’ for which the Second Vatican Council was convened,” said Nicastro.

For most of the first millennium, Orthodox and Catholics lived in full communion while developing varying expressions of Christian life, said Nicastro, but in the second millennium this unity gradually broke down. “Now, the Holy Spirit is moving among us to heal the breach,” he added.

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