London, Aug 16 (IANS): Pope Francis Saturday conducted a large open air mass in Seoul to beatify 124 of South Korea's first Catholics.

He paid tribute to the Koreans, who died for their faith in the 18th and 19th centuries, and who were the founders of the church in the region, BBC reported.

"They were willing to make great sacrifices and let themselves be stripped of whatever kept them from Christ - possessions and land, prestige and honour - for they knew that Christ alone was their true treasure,'' Pope Francis told the crowd in his sermon.

"They challenge us to think about what, if anything, we ourselves would be willing to die for.''

The beatification ceremony was held at Gwanghwamun Square in central Seoul with hundreds of thousands of people in attendance.

Beatification, or declaring a person "blessed", is a necessary prelude to full sainthood.

Pope Francis arrived Thursday in South Korea, beginning his first visit to Asia since he took over the papacy in March 2013.

The pope met survivors of the Sewol ferry disaster and delivered his first public mass Friday at a football stadium in Daejeon, his first public event since arriving in South Korea.

The South Korean Catholic Church is one of the fastest growing in the world with around 5.4 million members, some 10.4 percent of the population.