Pope Francis is conducting a large open-air Mass to beatify 124 of South Korea’s first Catholics at a ceremony in the capital Seoul on Saturday.
He will pay tribute to the Koreans, who died for their faith in the 18th and 19th Centuries.
It comes on the third day of his visit to South Korea – his first trip to Asia since becoming pope in March 2013.
Pope Francis met survivors of the Sewol ferry disaster and delivered his first public mass in the region on Friday.
The beautification ceremony will be held at Gwanghwamun Square in central Seoul, with up to one million people expected to be in attendance.
Beatification, or declaring a person “blessed”, is the necessary prelude to full sainthood.
‘Spiritual desert’
The Pope is spending five days in South Korea, where the Catholic Church is growing. It currently has just over 5.4 million members, some 10.4% of the population.
Hundreds of thousands have turned out for Saturday’s ceremony on Gwanghawmun plaza – where unrepentant Catholics were paraded before they were publicly executed.
On Friday, Pope Francis held Mass for tens of thousands of people gathered at a football stadium in Daejeon, his first public event since arriving in South Korea.
In his address, the pope warned Catholics of a “cancer” of despair in materially-obsessed societies, saying that materialism was spreading like a spiritual desert across the affluent world.
He urged Catholics in South Korea to combat the allure of materialism in his address
Before Mass got underway, he met with some of the survivors and relatives of the South Korean ferry disaster that killed more than 300 people in April this year.
He was later greeted by a rapturous crowd of some 10,000 youths in Dangjin, where he spoke briefly off-the-cuff in English, acknowledging his difficulties with the language.
There he urged South Koreans to pray for unification with the north.
“Let us pray for our brothers in the north,” he said.
Meanwhile, China’s leadership failed to receive a telegram sent by the Pope as he flew over the country on his way to South Korea, Vatican spokesman Federico Lombardi said on Friday.
It is traditional for the pontiff to send blessings to the leadership of a country he flies over, but this was the first time a pope had been permitted to use Chinese air space.
The gesture is seen as significant because the Vatican and China have had no formal ties since the Communist party took power in 1949.
A technical glitch was thought to have stopped the message from being received, which was later resent via the Italian embassy in Beijing, Mr Lombardi said. BBC