Pope Francis has departed the Vatican for Myanmar on the first papal visit to the country that has this year been widely accused of ethnic cleansing.
Focus will be likely be on whether he uses the term "Rohingya" to describe the country's Muslim minority.
Myanmar officials strongly reject the term, raising concerns it could spark some potential violence if he does.
He is scheduled to meet Myanmar's de facto leader Aung San Suu Kyi, and the head of the country's military.
The Pope will then visit Bangladesh, and meet a small group of Rohingya refugees there in a symbolic gesture. The 80-year-old pontiff has become known for his liberal views and willingness to denounce global injustice.
More than 600,000 people have fled to neighbouring Bangladesh since August when attacks on police posts prompted a military crackdown in the Rakhine state since August.
The Pope used the term "our Rohingya brothers and sisters" while denouncing the persecution then, but Myanmar's sole Catholic cardinal has asked him to avoid using it on the trip, fearing inflaming local insensitivities could lead to violence in the Buddhist-majority nation.
Myanmar officials do not use the term as they say the Rohingya migrated illegally from Bangladesh so should not be listed as one of the country's ethnic groups. They say the military crackdown in Rakhine is to root out violent insurgents there, but the UN described the violence as "textbook example of ethnic cleansing" - a sentiment echoed by international critics.
Last week Myanmar and Bangladesh signed a deal to return hundreds of thousands who have fled across the border, but aid agencies have raised concerns about any forcible return unless their safety can be guaranteed.
Papal aides say he will use the six-day trip to encourage dialogue and reconciliation after last week's tentative agreement.
The visit was organised before the crisis, when the Pope met the country's de facto leader Ms Suu Kyi at the Vatican in May. The former Nobel Peace Prize laureate has faced fierce criticism for her silence on the persecution of the Rohingya.
A large proportion of the 660,000 strong Catholic minority of Myanmar are expected to see him hold mass in Yangon.
He will then become the first Catholic leader to visit Bangladesh since 1986 when he arrives on Thursday.