Pope John Paul II devoted enormous spiritual and physical energy to his visits to the developing world. He undertook gruelling journeys despite his poor health in later years.
By Andrew Walker
But in Latin America the Vatican faced a dilemma - how to help the millions of Catholics living in extreme poverty.
Should the Vatican support priests who back revolutionary movements - what became known as liberation theology - or should it support the conservatives?
Pope John Paul II with Mother Teresa on a visit to India
In the early 1980s, this issue came to a head during a visit to central America. In Nicaragua there was a revolutionary Sandinista government, with five Catholic priests as ministers.
One of those priests was at the airport to greet the Pope. He was to experience papal disapproval at first hand during the visit.
Popular church condemned
To Pope John Paul II, the idea of a priest-politician was anathema. During his visit he condemned the so-called "popular church" created by left-wing priests as "a deviation".
The Pope always seemed more at ease on his visits to Africa - particularly South Africa after the end of apartheid.
Under the previous regime, the Catholic Church had been vilified as the "Roman Terror" - because of its opposition to racial segregation. But that had all changed.
The Pope seemed more comfortable visiting Africa - here with Nelson Mandela
Africa is the only area of the world where the number of priests is increasing, and John Paul II was aware that in the future there could be an African pope.
The most remarkable event of his many visits to Asia came when he celebrated mass in the Philippine capital Manila.
One million had been expected. In fact, four million turned out - making it the biggest papal mass in history.
The Philippines is Asia's only Catholic country, and he was regarded there as a saint.
In other Asian countries, however, relations with different religions were strained. In Sri Lanka, Buddhist monks were angry about comments on their faith made in a book by the Pope himself.
Another challenge to Catholicism comes from the new evangelical churches. Brazil has the largest Catholic population, but here hundreds of thousands have been tempted away by new churches which offer the poor the promise of instant prosperity.
Other parts of the world presented their own particular difficulties. Cuba, Communist since 1959, was one - an officially atheist state with a large Catholic population.
Fidel Castro was pleased to hear the Pope attack the US trade embargo
John Paul II did not visit Cuba until 1998. Despite his dislike of Communism he accepted an invitation from Fidel Castro who, though a critic of the Church, attended a papal mass.
The Pope was even-handed in his criticism of atheist Marxist states and of the excesses of capitalism.
Fidel Castro was particularly pleased to hear the Pope attack the American trade embargo.
But the main purpose was spiritual. In Santiago, a statue of the Virgin of Charity - the country's favourite icon - was paraded before an emotional papal mass.
The Pope's message to these Cubans and to all Catholics in the Third World was that even if they could not go to Rome, he would come to them - whatever the nature of the regime under which they lived.
John Paul II had a deep commitment to the developing world. He was an outspoken advocate for a better deal for the poor.
He did not, however, have any time for those in the Church who proposed radical political solutions to such great problems.