In his third overseas trip since being elected pope last year, Pope Francis celebrated Mass for 800,000 people, canonised 124 Catholic martyrs in South Korea, and attended the sixth Asian Youth Day for young Catholics from throughout Asia.
While the Korean martyrs died in persecutions during the 18th and 19th centuries, the more recent persecutions which took place during the Japanese occupation in the 1930s and 1940s, and the communist persecutions from the 1950s were not far from people's minds.
The 124 martyrs are just a tiny proportion of the estimated 10,000 Catholics executed for their faith during the persecutions at that time.
The papal visit was seen as recognition of the growing role of Christianity in Asia. Both Catholic and Protestant churches have grown very significantly in South Korea over recent decades, and the Catholic Church is widely seen as a source of moral authority in the community.
Pope Francis undoubtedly was also conscious of the geographic realities facing South Korea which exists under constant threat from the Communist north.
Thousands of Catholics continue to face daily persecution in North Korea and China, where the Communist Party has alternately attempted to suppress and control the Church.
The Pope's friendly informality – including posing for "selfies" with young people, and travelling around in a small Kia sedan rather than a luxury car – impressed people as much as his condemnation of unbridled capitalism and his identification with the poor.
Confirming the Church's unchangeable teaching on abortion, the Holy Father visited and prayed at a small cemetery for aborted babies in a visit to a home for the poor and disabled about 120 km from Seoul.
The visit was important, as South Korea is believed to have one of the highest abortion rates in the world, despite it being illegal except in the case of rape or incest.
On a number of occasions during his historic visit, the Pope called for reconciliation between North and South Korea.
At a Pontifical Mass in Seoul's Myeongdong Cathedral, the Pope called for the two Koreas to work together. He appealed for "the emergence of new opportunities for dialogue, encounter and the resolution of differences, for the continued generosity in providing humanitarian assistance to those in need."
Pope Francis' visit to South Korea also threw the spotlight on a Church which is unashamedly evangelical, and growing rapidly.
The number of Catholics in South Korea has doubled since 1990 to 5.4 million, or just over 10% of the total population, with about 100,000 baptisms a year. The number of new priests has risen 17% since 2008 and many are young, in contrast to the sharp decline in priests in the West.
The growth of the Church has accompanied the country's growing economic prosperity. "Although the Korean church is small, in terms of its fervency, it stands out," Sebastian Kim, an academic, told the Wall Street Journal.
Another important element of the establishment and growth of the Korean Church has been the role of lay men and women.
Unlike the Church in most other countries, the foundations of Catholicism in Korea were exclusively lay people. The clergy followed many decades later.
The importance of the laity persists today. Lay people often lead small prayer or Bible study groups and invite neighbours and family to join, taking a page from the grassroots evangelisation employed with huge success by many Protestant denominations in South Korea.
Lay people who serve as lectors during Mass sometimes wear special robes that exalt their presence on the altar, while lay members of a church often flock to funerals of non-relatives to offer prayers and hymns.
Another contributing factor in the growth of Catholicism has been the role played by the Church in fighting for democracy and resisting the military dictatorship which ruled South Korea for decades.
For instance, the late Cardinal Stephen Kim, Korea's first cardinal, sheltered students protesting the dictatorship in his cathedral and exposed the practice of police torture. His cathedral in Seoul became known as a refuge for democrats and dissenters.
The Church also runs an extensive network of health, educational and charitable institutions. It runs 40 hospitals, 277 orphanages and daycare centres and over 500 centres for the elderly and disabled, according to Vatican figures, and has provided humanitarian relief to North Korea.
In South Korea, Protestants outnumber Catholics two to one, so Pope Francis held a special meeting with other religious leaders.
During his visit, Pope Francis appealed to the leaders of China and North Korea to open the doors. In a speech reminiscent of US President Ronald Reagan's appeal to Soviet President Gorbachev to "tear down this [Berlin] Wall", Pope Francis urged the establishment of direct relations with neighbouring countries.
While addressing bishops south of Seoul he referred cordially to China and other Asian nations with which the Vatican does not have formal relations, in his strongest outreach yet to those governments:
"In this spirit of openness to others, I earnestly hope that those countries of your continent with whom the Holy See does not yet enjoy a full relationship may not hesitate to further a dialogue for the benefit of all."
"I'm not talking here only about a political dialogue, but about a fraternal dialogue," the pope added, assuring that "Christians aren't coming as conquerors" to strip away any nation's "identity." The important thing, he said, was to "walk together."
While flying above China, the Pope broadcast via radio telegram a message to Xi Jinping, the Chinese president and party leader, offering his best wishes and blessings of peace.
Pope Francis has made an impressive impact on South Korea which will be felt for years to come.