As the Pope visits Jordan, Israel and the West Bank, he faces an combustible cocktail of issues combining relations between the world's three main monotheistic religions, one of the world's most intractable political conflicts and the legacy of the Holocaust. The BBC News Website looks at the areas of controversy he will have to navigate.
The Catholic Church has moved in recent decades to make amends for a long history of anti-Semitism.
In the 1960s it reversed its centuries-old policy of blaming the Jews for the death of Jesus and altered a prayer used on Good Friday which called for the conversion of Jews and described them as "faithless" - sometimes translated as "treacherous".
Pope Benedict XVI's predecessor, John Paul II, made efforts to improve relations. He spoke of growing up with Jewish friends in Poland and was the first Pope to visit both a synagogue and the site of the Auschwitz gas chambers.
It was under him that the Vatican, long seen as pro-Palestinian by many Jews, finally established diplomatic relations with Israel after the 1993 Oslo peace accords.
He made a historic apology for the wrongs done to Jews by Catholics over the centuries, and visited the Holocaust Memorial Yad Vashem and the Western Wall on his trip to the Holy Land in 2000.
But some Jewish groups felt he had not gone far enough, in not specifically mentioning the silence of the Vatican during the Holocaust.
Pope Benedict arrives with a more problematic background. As a young German he joined Hitler Youth at the age of 14, as was mandatory at the time. But he has since spoken of how his teenage years were "marred by a sinister regime". He later served in the German military, but deserted towards the end of WWII.
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