Pope Francis started a landmark, three-day visit to the United Arab Emirates on Sunday, becoming the first pontiff of the Roman Catholic Church to visit the Arabian Peninsula.

The visit offers a rare note of hope for Christians in the Middle East, who in recent decades have come under intense pressure in the region where their faith has its roots. Many have been persecuted, killed or forced to flee.

[Read more: A ‘Historic’ Gulf Tour Amid Yemen Crisis and Christian Repression]

The pope’s presence in the Gulf — an area where religious freedom has traditionally been highly restricted — will shine a light on the broader role of Christianity in the Middle East. Before his plane took off, the pope also addressed the situation in Yemen, where a dire humanitarian crisis is unfolding — a pointed intervention because his Emirati hosts are among the war’s leading belligerents.

Christianity has been threatened, particularly in the Gulf.

Wars, jihadist violence and sectarian tensions have reduced the proportion of Christians in the Middle East to about 4 percent of the population today, from about 20 percent before World War I, according to the Vatican.