Pope Francis began a lightning visit to European institutions in Strasbourg on Tuesday where he was expected to call for a "tired" Europe hit by economic crises and surging nationalism to reclaim a leadership role.
Francis will leave his popemobile behind and -- unusually for the crowd-loving Argentine -- dedicate his time to addressing the European Parliament and the Council of Europe in a four-hour trip, the shortest abroad by any pope.
Wearing a white coat to protect him from the cold, the pontiff descended the steps of an Alitalia plane on arrival in the eastern French city and took part in a brief welcoming ceremony, an AFP journalist travelling with him said.
In what is the second visit by a pope to the parliament in Strasbourg after John Paul II in 1988, Francis will also meet briefly with new European Commission chief Jean-Claude Juncker and outgoing European Council President Herman Van Rompuy.
"It`s going to be a big day," the 77-year-old pope, looking pale and tired but calm, told journalists on the plane.
Security was tight across Strasbourg with snipers posted on the top of buildings at the European Parliament and army sniffer dogs sent out to check the area before his arrival.
The climate has changed greatly since the last papal visit and Vatican watchers say the pontiff will have to fight harder to be heard in an increasingly secular continent.
Crowds of faithful are expected to watch the speeches on giant screens set up in front of the city`s cathedral.
For protocol reasons the head of the Catholic Church will be driven between the parliament and council buildings rather than walking, the Vatican said ahead of the trip.
Francis has in the past dubbed Europe a "tired" continent which has lost its way, and he may repeat such warnings amid a rise in radicalisation, particularly among the disillusioned younger generation.
He is expected to call for greater tolerance, social inclusion and dialogue as a recourse to an increase in racism in countries hit hard by the economic crisis, where nationalist, Eurosceptic and anti-immigration parties are thriving.
His visit has sparked protests in some quarters -- including from a bare-breasted Femen rights group demonstrator who mounted the altar in Strasbourg cathedral on Monday -- with critics slamming European Parliament head Martin Schulz`s decision to invite a religious leader to address a secular body.
Schulz defended the invitation in an editorial for the Vatican Osservatore Romano newspaper this weekend, saying the visit could "shake Europe out of its torpor" and was by no means "an attack on secularism."
The pope`s right-hand man, Vatican Prime Minister Pietro Parolin, said Francis`s message would have a strong social dimension, calling on Catholics to make their "own contribution" to the European project, while showing "solidarity with the marginalised."
The leader of the world`s 1.2 billion Roman Catholics will likely call for more to be done to tackle youth unemployment -- which stands at an average 21.6 percent in the continent -- and to care for those fleeing war zones and persecution, as well as the elderly.
Many, particularly in the Church`s conservative arm, will be watching closely to see whether Francis will address hot-button topics such as gay marriage, abortion and euthanasia -- particularly after a slew of recent legislative changes in European countries.