11:45PM BST 23 Sep 2011
Visiting the monastery in Erfurt where Martin Luther lived before launching the Reformation, the pontiff praised Luther's "deep passion and driving force" and called for unity between the Catholic and Protestant faiths in the face of a new evangelism.
He launched a thinly veiled attack on the evangelical and Pentecostal churches which have been attracting converts from more established faiths, especially in developing countries.
"Faced with a new form of Christianity, which is spreading with overpowering missionary dynamism, sometimes in frightening ways, the mainstream Christian denominations often seem at a loss," said the pope. "This is a form of Christianity with little institutional depth, little rationality and even less dogmatic content, and with little stability. This worldwide phenomenon poses a question to us all: what is this new form of Christianity saying to us, for better and for worse?"
The 84 year old pontiff paid tribute to Luther, the theologian who disputed Church tenets sparking a split among German Christians that led to the creation of the Lutheran church.
Benedict said: "What constantly exercised him was the question of God, the deep passion and driving force of his whole life's journey."
But the Pope was seen to fall short of offering a tangible olive branch, after deflecting appeals to relax rules barring protestants from receiving the Catholic eucharist.
Germany's top Protestant bishop urged the Vatican to take "real steps for reconciliation" ahead of the upcoming 500th anniversary of the Reformation in 2017, which the Protestants would like to mark with Catholic participation.
On the afternoon of second day of the state visit to his native Germany, the pontiff travelled to the pilgrimage site of Etzelsbach, near Heilbad Heiligenstadt, in the former East Germany, to honour those Catholics who helped resist communist rule.
The tiny chapel was popular with farm workers living under communist rule who visited the site to pray for the health of their animals.
