Rome. Pope Francis will preside over an interfaith meeting in a mosque in the world’s largest predominantly Muslim country during a four-nation Asian visit in September that will be the longest and most complicated foreign trip of his pontificate.

The Vatican on Friday released the itinerary for Francis’ Sept. 2-13 trip to Indonesia, East Timor, Papua New Guinea and Singapore. The packed schedule makes clear that the 87-year-old pontiff, who has battled health problems and is increasingly reliant on a wheelchair, has no plans to slow down.

After a day of rest upon arrival in Jakarta on Sept. 3, Francis launches into a typically rigorous round of protocol visits to heads of state and government, speeches to diplomats and meetings with clergy and public Masses.

Francis will be the third pope to visit Indonesia, after Pope Paul VI in 1970 and Pope John Paul II in 1989. About 87 percent of Indonesia’s 277 million people are Muslim, but the country also has Southeast Asia’s second-largest Christian population, after the Philippines, and the third-largest in Asia after the Philippines and China.

In Jakarta, he’ll preside over an interfaith meeting at the capital’s Istiqlal Mosque, expected to be attended by leaders of the six religions in Indonesia that are officially recognized and protected: Islam, Protestant, Catholic, Buddhism, Hinduism and Confucianism.

Francis is also expected to walk through a tunnel, called the “Tunnel of Friendship,” connecting the grand mosque to the neo-Gothic Our Lady of The Assumption Cathedral, which was constructed by Indonesian authorities in 2020.

As a result, the first leg of Francis' four-nation trip is likely to heavily emphasize interreligious harmony and tolerance, a theme he has hammered home on many of his foreign visits, especially to the Gulf and other Muslim-majority nations.

Sprinkled in the mix in all four countries are encounters with young people, poor and disabled people, elderly people and Francis’ regular meetings with his Jesuit confreres.

The trip was originally planned for 2020 but was called off because of the COVID-19 pandemic. At 11 full days, it's the longest of Francis’ 11-year papacy, outpacing by a few days some of his long trips to the Americas and recalling some of the strenuous, globe-hopping trips of St. John Paul II.

It will bring the Argentine Jesuit to Indonesia, as well as one of the world's newest countries, the former Portuguese colony of East Timor, where the Catholic Church wields enormous influence.

About 98.3 percent of its 1.34 million population is Catholic, according to the 2022 census, and it’s the Asian country with the highest proportion of Catholics after the Philippines.

Francis will be the second pope to visit East Timor after John Paul in 1989, but the first since the country gained independence from Indonesia in 2002.

In East Timor, however, Francis may also have to reckon with the legacy of independence hero Bishop Carlos Ximenes Belo. The Nobel Peace Prize winner was sanctioned by the Vatican in 2020 for having sexually abused young Timorese boys and is currently believed to be living in Portugal.

Francis had to cancel his last planned foreign visit -- a quick trip to Dubai last year to participate in the UN climate conference -- because of a recurring case of bronchitis. He has seemed in relatively good form in recent months, including during day trips to Italian cities and visits to Roman parishes.

But in recent years, as his mobility has been limited by bad knee ligaments, he has generally stuck closer to home and kept his foreign trips relatively short.

After he returns to Rome in mid-September, he has a four-day visit to Belgium and Luxembourg before the end of the month, the only other foreign trip that has been confirmed for the year.