ROME – Making official what the Swiss government had already announced, the Vatican confirmed on Friday that Pope Francis will travel to Geneva, Switzerland, on June 21 to mark the 70th anniversary of the World Council of Churches in one of the traditional centers of the Protestant Reformation.

“His Holiness has in mind to visit the World Council of Churches in Geneva on the occasion of the 70th anniversary of its foundation,” Vatican spokesman Greg Burke announced on Friday in the Vatican’s daily news bulletin.

“The visit will take place Thursday, June 21, 2018,” Burke said. “The program of the trip will be published soon.”

With 348 member churches in 110 nations, the World Council of Churches (WCC), founded in 1948, is the largest umbrella group of Christian denominations in the world. It includes most Eastern Orthodox churches, the Anglican Communion, most mainline Protestant churches and several Evangelical denominations.

The Catholic Church is not a member of the WCC, although it does send observers to meetings and events.

The trip will be the second European outing by Francis with a clear ecumenical thrust, after an Oct. 31, 2016 visit to Lund in Sweden to mark the 500th anniversary of the Protestant Reformation in tandem with leaders of the Lutheran World Federation.

The Vatican confirmation of the trip came just ehad a news conference on Friday featuring Swiss Cardinal Kurt Koch, President of the Vatican’s Pontifical Council for Promoting Christian Unity, and the Rev. Olav Fykse Tveit, a Norwegian Lutheran theologian and General Secretary of the WCC.

Asked about why the Catholic Church is not a member of the WCC, Koch said that the papal office has a special responsibility as an agent of Christian unity, and it would be inappropriate to confuse that with the role of other ecumenical agencies and instruments.

Tveit suggested that focusing on the question of membership puts the emphasis in the wrong place.

I think we live very well with the relationship we have today, we don’t focus on this question of membership but what we can do together,” he said.  “I think that’s where we should focus our energy right now.”

Swiss Federal Council spokesman Andre Simonazzi said on Thursday that details of the June 21 visit are being worked out, adding only that President Alain Berset would welcome Francis.

St. John Paul II was the last pope to visit Switzerland, in 2004, one of his last trips. The last papal visit to Geneva was also by John Paul II in 1984, during a six-day pastoral visit to the country.

A total of 38.2 percent of Swiss people are Roman Catholic while 26.9 percent belong to the mainstream Protestant church, according to official Swiss figures.

During the era of the Protestant Reformation in the 16th century, French theologian John Calvin established his base in Geneva, often exercising influence not only over church life but also the city council and city affairs. His theological ideas, including predestination, the absolute sovereignty of God over all of human life, and the importance of personal probity and industriousness, formed the basis of what came to be known as “Calvinism” and continue to form one of the most important currents in global Protestantism.

Tveit said the initial invitation for the trip was presented to Pope Francis in a meeting in Rome last August.

“We described in fraternal way the relationship we have, and asked if this 70th anniversary could be occasion to visit the World Council of Churches and to give new power, new expression, to this collaboration,” he said.

Asked if it had been difficult to convince the pontiff to make the trip, Koch delivered a one-word answer: “No.”