ROME—After staying largely quiet and hidden since his resignation, emeritus Pope Benedict XVI will make a rare public appearance on June 28 to mark the 65th anniversary of his priestly ordination. Pope Francis is scheduled to attend the event, to be held in the Vatican’s Apostolic Palace.

The celebration was announced by the Vatican’s “Ratzinger Foundation”, created in honor of the retired pope, whose given name is Joseph Ratzinger.

Benedict was ordained on the feast of Sts. Peter and St. Paul, June 29, in 1951, in the Cathedral of Saint Mary and Saint Corbinian in Freising, Germany. He was one of 40 new priests ordained in that ceremony, including his brother Georg.

In his biography “Milestones, Memoirs 1927-1977,” the retired pontiff described the date as a “radiant summer day,” of which he wrote: “We should not be superstitious, but at the moment when the elderly archbishop laid his hands on me, a little bird – perhaps a lark –  flew up from the high altar in the cathedral and trilled a little joyful song.”

“And I could not but see in this a reassurance from on high,” he wrote, “as if I heard the words, ‘This is good; you are on the right path’.”

The late archbishop he referred to was Cardinal Michael von Faulhaber of Munich, who died the next year.

The possibility of a celebration to mark the anniversary of Benedict’s ordination was first revealed by his personal secretary and the head of the papal household, Archbishop Georg Gänswein, back in May, when he said the anniversary might “present an opportunity to show that Benedict XVI is well.”

The German pontiff has rarely appeared in public since he stepped down from the papacy in February 2013. He’s attended the two consistories for the creation of new cardinals, held in February of 2014 and 2015. He was also present for a “Festival of Grandparents” which took place in September of 2014, and he attended the canonization Mass for popes John XXIII and John Paul II.

Except for some rare pictures of private visits to his home within Vatican grounds, the Mater Ecclesiae monastery, Benedict was last seen in public on Dec. 8 2015. On that occasion, he was the first pilgrim after Pope Francis to go through the Holy Door in St. Peter’s Basilica, at the inauguration of the Jubilee Year of Mercy.

The pope and his predecessor have also shared some private meetings. For instance, in 2013, right after his election, Francis’ flew in helicopter to Castel Gandolfo, the papal summer residence where Benedict spent the first days of retirement.

Francis has openly praised Benedict in several occasions, particularly when speaking of the German pontiff’s response to clerical sexual abuse. On his way back from Mexico in February, Francis asked the journalists travelling with him for a round of applause for Benedict for his response to this crisis.

“[Ratzinger] was the brave one who helped so many open this door,” Francis said at the time. “I want to remember him because sometimes we forget about these hidden works.”

On April 16, which was Benedict’s 89th birthday, through the papal Twitter account, Francis asked the millions who follow him to “thank God for giving him to the Church and the world.”

The last time Benedict broke his self-imposed silence was last May when, through the Vatican’s press office, he released a statement denying there’s more to the third secret of Fatima than what was revealed during John Paul II’s papacy in 2000.