As he approaches the 25th anniversary of his papacy, Pope John Paul II is a picture of extreme fragility and sheer determination, of surprising resilience and severe physical limitations.
A hero to conservative Roman Catholics who see him as a fixed star shining on a world in moral flux, a disappointment to liberals who dared hope he would move the church their way, the pope is unquestionably among the most important religious figures of the last century.
Yet, in what even he calls his "twilight years," John Paul's reign has largely been about a painful, personal struggle with declining health while his legacy suffers from the effects of clergy sex abuse scandals, mainly in the United States and Europe.
It all makes for a bittersweet moment as the church prepares to mark the anniversary of John Paul's election on Oct. 16, 1978.
The Vatican has invited the entire College of Cardinals to Rome for nearly weeklong celebrations, along with the president of each national bishops' conference and a delegation of prelates from John Paul's native Poland. There will be an anniversary day Mass that is expected to attract tens of thousands of Romans to St. Peter's Square, a concert in his honor and a luncheon with all of the cardinals.
The festivities continue with the Oct. 19 beatification of Mother Teresa of Calcutta -- the tiny nun who devoted her life to the poor. John Paul was so impressed with her work that he put the nun, who died six years ago, on the fast track to sainthood.
Events conclude two days later with the installation of 30 new cardinals, whose nomination last month was a sign of the pope's intent to influence the choice of a successor.
Indeed, there is much to celebrate. This is a pope who will be remembered for helping end communist rule in eastern Europe by sparking what amounted to a peaceful revolution in his homeland; for seeking to heal divisions between Christians and Jews; and for traveling around the globe to greet his 1-billion-member flock.
He has been a constant voice for peace. In 1984, he stepped in and mediated a territorial dispute between Chile and Argentina when the two mainly Catholic South American neighbors were on the brink of war.
John Paul was more successful there than in opposing both the 1991 Gulf War and the U.S.-led invasion of Iraq this year. Still, he has been persistent: In the aftermath of the Sept. 11, 2001, attacks, the pope has repeatedly denounced violence committed in the name of religion.
He also has tried to develop warmer relations with Jews, extending the Vatican's full diplomatic recognition to Israel, becoming the first pontiff to visit the main Rome synagogue, repeatedly denouncing anti-Semitism and issuing a statement of Christian contrition over the Holocaust.
"John Paul will go down in history as the most important world leader in the second half of the 20th century," said the Rev. Thomas Reese, editor of the Jesuit magazine America.
At 83, John Paul is a stooped figure, suffering since the mid-1990s from Parkinson's disease and crippling knee and hip ailments. The Vatican -- adapting to his weakened condition -- has devised a throne-like chair on wheels that allows him to celebrate Mass while seated.
During birthday celebrations at the Vatican in May, he told his fellow Poles that "I am increasingly aware that the day is drawing near when I will have to present myself to God and make an accounting of my whole life."
John Paul, however, still has ambitions. His spokesman says the pope is finishing a book on his days as a bishop and still may accept invitations for visits next year to Austria, Switzerland and France as well as a return to his homeland.
Certainly, one of the pope's greatest sorrows has been the inability to achieve reconciliation with the Orthodox Church. Beyond theological differences over papal supremacy, relations with the Russian Orthodox Church have worsened since the fall of communism.
The Russians have expressed alarm over the Vatican's missionary advances in traditional Orthodox territory once communism-era persecution of Catholics ceased. Orthodox leaders have thwarted John Paul's desire to become the first pope to visit Russia.
"The greatest disappointment of his papacy must be that a liberated eastern Europe did not become a force for the spiritual renewal of the West, but rather the West with its individualism and consumerism has corrupted the East," Reese, the magazine editor, said.
When all is said and done, John Paul's supporters will argue that the pope's accomplishments far outweigh the problems of his reign, giving Catholics reason to take pride in his anniversary.
Said Navarro-Valls: "John Paul is a realist. He doesn't allow disappointments to get to him."