VATICAN CITY — Pope Benedict XVI could appear in public once again on June 29, the 65th anniversary of his priestly ordination.

Speaking after the May 20 presentation of a book dedicated to Benedict XVI’s pontificate, Archbishop Georg Ganswein, prefect of the pontifical household and private secretary to the retired pope, said that “there will be another occasion to see the pope emeritus in public.”

“Benedict XVI will celebrate the 65th anniversary of [his ordination] June 29, and we will see what we will be able to manage. … This may present an opportunity to show that Benedict XVI is well.”

The Catholic Church celebrates the martyrdom of Peter and Paul on June 29, patron saints of the city of Rome. On this feast, newly created metropolitan archbishops celebrate Mass with the Pope in St. Peter’s Basilica and receive the pallium, the primary symbol of their office.

Benedict XVI has appeared in public half a dozen times since he stepped down three years ago.

He took part in both of Pope Francis’ first two cardinal-creating consistories, held Feb. 22, 2014, and Feb. 14, 2015. He was also present Sept. 27, 2014, at the “Festival of Grandparents.” He concelebrated the canonization Mass of Sts. John XXIII and John Paul II on April 27, 2014, and he took part in Paul VI’s beatification Mass Oct. 19, 2015. He was also the first pilgrim to pass through the holy door after Pope Francis at the inauguration of the Jubilee of Mercy on Dec. 8, 2015.

Pope Francis and Benedict XVI have also had several private meetings, some of them documented with pictures.

Pope Francis visited Benedict XVI at Castel Gandolfo on March 23, 2013, and he welcomed the retired pontiff back in the Vatican on May 2 of that year. The two popes together blessed the St. Michael the Archangel statue displayed in the Vatican Gardens on July 5, 2013.

Pope Francis also went to wish Benedict XVI Christmas greetings Dec. 23, 2013, and the retired pope, in turn, had lunch with Pope Francis at the St. Martha guesthouse on Dec. 27, 2013.

If Benedict does make a public appearance June 29, it would commemorate a very powerful moment in his life and ministry.

Joseph Ratzinger — who would become Benedict XVI — was ordained a priest June 29, 1951, in the Cathedral of St. Mary and St. Corbinian in Freising, Germany.

Later, in the same cathedral, he recalled the event, speaking off the cuff to priests and permanent deacons on Sept. 14, 2006.

On that occasion, a visibly moved Benedict XVI recounted: “Now that I am back in this cathedral, many memories come to me, as I see before me my old companions and also the young priests who are handing on the message, the torch of the faith. Memories of my ordination, of which Cardinal [Friedrich] Wetter has spoken, come to mind.”

Looking at the altar, Benedict XVI went on to say: “Here, I lay prostrate, enveloped by the litany of all the saints, by the intercession of all the saints. I realized that on this path we are not alone, that the great multitude of saints walk with us, and the living saints, the faithful of today and tomorrow, sustain us and walk with us. Then came the Laying on of Hands; and, finally, Cardinal [Michael] Faulhaber proclaimed to us: Iam non dico vos servos sed amicos — ‘I do not call you servants, but friends’; at that moment, I experienced my priestly ordination as an initiation into the community of Jesus’ friends, called to be with him and to proclaim his message.”