Pope holds Mass celebrating Poland's deep Catholic roots

Pope Francis prays in front of the Black Madonna in the Jasna Gora' shrine in Czestochowa, Poland, Thursday, July 28, 2016. (AP Photo/Gregorio Borgia, Pool)

CZESTOCHOWA, Poland -- Pope Francis, visiting a shrine cherished by Poles, praised native son St. John Paul II on Thursday and honoured the countless "ordinary yet remarkable people" in Poland who held firm to their Catholic faith throughout adversity in the former Communist nation.

The Argentine pontiff, who had never set foot in Eastern Europe before this week's five-day pilgrimage to Poland, gazed in apparent awe for several minutes as he studied the Jasna Gora monastery shrine's iconic image of the so-called Black Madonna. The faces of Mary and Baby Jesus in the icon -- an object of veneration starting in the 14th century -- are blackened by centuries of varnish and candle soot.

A silver screen was raised slowly and dramatically to unveil the image as Francis stood silently and then prayed.

Then, during an outdoor Mass in the southern city of Czestochowa before a crowd that organizers put at 600,000, Francis lavished praise on Poland's legacy of steadfast devotion as he urged Poles to hold fast to their faith.

As the 79-year-old pope walked up to the altar he tripped and fell, but quickly rose, helped by priests, and went on to deliver a long homily. Church officials said Francis was not hurt and did not complain afterward.

The Mass was held in celebration of this year's 1,050th anniversary of Poland's acceptance of Roman Catholicism. The baptism of a medieval king in 966 put Poland on course to be part of the Latin-speaking Western world, setting it apart culturally from Orthodox nations in the region. Polish President Andrzej Duda and other political leaders were among those attending the Mass.

"Our minds turn to so many sons and daughters of your own people, like the martyrs who made the defenceless power of the Gospel shine forth, like those ordinary yet remarkable people who bore witness to the Lord's love amid great trials," Francis said in his homily, speaking in Italian and pausing for a priest to translate his words into Polish.

He cited two beloved Polish saints, praising those "meek and powerful heralds of mercy who were Sts. John Paul II and Faustina. Through these channels of his love, the Lord has granted priceless gifts to the whole Church and to all mankind."

Francis then recalled the far less famous soldiers of the faith in Poland.

"Your own history, shaped by the Gospel, the cross and fidelity to the church, has seen the contagious power of a genuine faith, passed down from family to family, from fathers to sons and above all from mothers and grandmothers, whom we need so much to thank," he said.

Francis urged Poles to stay united even as their nation is divided over the issue of refugees and migrants, especially those who aren't Christians. He prayed that Poles would have "the desire to leave behind all past wrongs and wounds, and to build fellowship for all, without ever yielding to the temptation to withdraw or to domineer."

The right-wing government which came to power in Poland last year has faced international suspicion that it has eroded past democratic gains, and critics say there has been a rise in xenophobic sentiment.

Worry about bad weather prompted a last-minute change the pope's travel plans, with Francis opting to take a car instead of a military helicopter to Czestochowa, 100 kilometres (60 miles) from Krakow. He returned to Krakow by helicopter.

Francis' visit to Poland centres on a Catholic youth jamboree that has drawn hundreds of thousands of participants.

After resting in the afternoon the residence of the Krakow archbishop, Francis rode in an electric tram through the heart of Krakow with disabled young people -- a gesture underlining his mission to fight climate change and encourage more humanity for the disadvantaged.

As archbishop of Buenos Aires in his native Argentina, he rode public transport to inspire humility among church hierarchy.

In place of the usual destination indicator on the tram were the words "Tram del Papa" -- Italian for "the pope's tram." He rode it to Blonia, a park where he was joining tens of thousands of young Catholics participating in World Youth Day, a global gathering which runs through Sunday.

The mood ahead of his arrival was joyful, with people singing and dancing to lively tunes as they waved flags from places as different as Tennessee and Turkey. Security was tight following a string of attacks in Europe, and people were warned over loudspeakers not to leave their bags unattended.

Monika Scislowska in Krakow and Vanessa Gera in Warsaw contributed to this report