On April 15, Pope Benedict XVI  is scheduled to arrive in the United States for a six-day visit -- his first trip to this country since being elected pontiff three years ago.

Joseph Ratzinger was born on April 16, 1927 in the village of Marktl am Inn in Bavaria -- a staunchly Catholic region in southern Germany. His father was a policeman and his mother was a homemaker. During his first 12 years, he moved five times throughout Bavaria as his father accepted various law enforcement positions.

In 1933, Adolf Hitler was appointed Germany's Chancellor. In 1939, Ratzinger entered a seminary in Traunstein. And later that year, the World War II broke out.

John Allen -- one of Ratzinger's biographers -- says soon after, he was forced to become a member of the Hitler Youth. "In 1943, membership in the Hitler Youth became mandatory for anyone who was enrolled in a German school. So he was put on the books as a Hitler Youth member, but he never took part in it," says Allen. "And in fact, he found a sympathetic teacher who allowed him to continue coming to classes, even though he didn't have his Hitler Youth card, which, in theory, all German youth were supposed to have."

Wartime Experiences

Allen says Ratzinger and his fellow seminarians were also pressed into part-time auxiliary military roles -- assigned to an anti-aircraft defense corps at a BMW munitions factory outside of Munich. He was then drafted into the army.

Brennan Pursell -- another Ratzinger biographer -- says that in the waning days of the Second World War, Ratzinger deserted. "He just said, 'Forget it, I'm going home,' and he walked out of his barracks. He had his arm in a sling because he had injured his thumb and he ran smack into two S.S. guys [i.e., members of an elite Nazi military organization]. And you should know that historians have roughly counted 20,000 executions of deserted German soldiers, probably mostly toward the end of the war," says Pursell. "And the S.S. guys could have easily said, 'You're a deserter,' and killed him on the spot. There are many instances of this. But they looked at him, looked at his thumb and said, 'You're wounded, comrade, on you go.'"

Ratzinger returned home to Traunstein, continued his theological studies and was ordained a priest in 1951.

John Allen says Ratzinger's wartime experiences had a profound influence on shaping his view of the role of the Catholic Church. "His diagnosis is that even though the Nazis are gone, there are still powerful ideologies out there in the world that would like to co-opt the church in one way or another. And the only way for the church to protect itself is to be as clear as possible about its identity, about its doctrine, its practice, its language, its thought," says Allen. "And so, I think his strong defense of traditional Catholic identity, which is still very much at the heart of his pontificate today, in some ways was forged in that crucible of National Socialism [i.e., Nazism]."

A Growing Influence in the Church

After his ordination, Ratzinger embarked on an academic career, teaching at prestigious universities including those in Bonn, Munster and Tubingen. In the mid-1960s, Ratzinger served as a theological adviser to the Second Vatican Council [from 1962 to 1965] that brought about major changes in the Catholic Church.

Biographer John Allen says that in the mid-1970s, Ratzinger began a correspondence with a man who would have a great influence on his life -- Cardinal Karol Wojtila. "They didn't actually meet, however, until [Pope] Paul VI made Ratzinger a cardinal in 1977. And then, of course, they met at the consistory where Ratzinger became a cardinal; they got to know one another," says Allen. "And then, obviously, they spent a lot of time together in 1978 because that was the year of the 'three Popes' -- Paul VI died, John Paul I was elected, then John Paul I dies 33 days later, and then Wojtila is elected."

As pontiff, Cardinal Wojtila took the name of John Paul II. And in 1981, he brought Ratzinger to Rome, naming him Prefect of the Congregation for the Doctrine of the Faith -- a position he would hold for almost a quarter of a century. Allen says he became the intellectual architect of John Paul II's papacy.

Father Thomas Reese of Georgetown University says Ratzinger's role as prefect was to be guardian of Catholic orthodoxy. "He has very definite ideas about theology that he believes other theologians should follow. And he has used his power to try to bring theologians around to his point of view," says Reese. "And sometimes that has involved silencing or disciplining theologians who he thinks have gone too far."

On Love and Hope

Cardinal Ratzinger was elected Pope three years ago, following the death of John Paul II. He took the name Benedict XVI.

Francesco Cesareo, President of Assumption College in Massachusetts, says many experts felt Pope Benedict would continue his hard-line approach. "He has not really been, in his writings, confrontational. Everyone was expecting his first encyclical [i.e., papal letter] to be the encyclical that cracks down on everything. And instead, it's on 'love'. And then his second encyclical is on 'hope.'"

Biographer John Allen describes Benedict's papacy as "affirmative orthodoxy". "The core of his papacy is a strong defense of traditional Catholic faith and doctrine -- that's the orthodoxy part -- but presented in the most relentlessly positive and upbeat fashion humanly possible. Ratzinger's feeling is that for 20 years it was his job to say 'no' -- that's what it means to run the Congregation for the Doctrine of the faith," says Allen. "Now he feels that he's in a position where he can say 'yes', that is he can talk about what Catholicism is 'for' and not what it's 'against.' And so that's why, for example, he devoted his first two encyclicals to the themes of 'love' and 'hope.'"

Looking ahead, Allen and others say do not expect anything revolutionary during Benedict's papacy. Experts say there has been practically no change from John Paul II to Benedict XVI.

This story was first broadcast on the English news program,VOA News Now. For other Focus reports click here.