The cheering crowds could not for long obscure the reality facing the quietly spoken man on whom all these smiling eyes were fixed.

Cardinal Jorge Mario Bergoglio gazed down on the tens of thousands who had come to greet him.

RTÉ Six One News presenter Bryan Dobson reflects on the election of Pope Francis from the rooftops of Rome

The enfolding arms of St Peter's Square stretched out beneath this Cardinal who we were told abandoned his bishop’s palace in favour of a simple apartment and travelled to work on the bus in his native Buenos Aires.

They cheered as appeared at the balcony and they cheered as he spoke, addressing them as the Bishop of Rome and inviting them to begin "a new journey... a pilgrimage of fraternity and love."

From our broadcasting position on a rooftop nearby we could hear, but not see, the huge crowd.

They had waited, some for hours, in the pouring rain, their numbers swelling as the daylight faded and a spotlight was switched on to the illuminate the Sistine Chapel chimney.

The smoke, when it came a few minutes after 7pm Italian time, was unmistakably white.

It billowed thickly from the thin pipe, telling Rome and the world that a Pope had been elected.

It was then the cheering began. Even before the new Pope was named the crowd was roaring its approval.

From beneath a canopy of umbrellas, pierced by flags and banners, the sheltering crowd clamoured for the news of who would be next to fill the shoes of the fisherman.

Who had been selected, we all wondered, to lead the Catholic Church in this time of exceptional challenges?

Not that many in the crowd appeared to be thinking of the problems facing the church as they celebrated this moment in history.

When the announcement finally came it took many by surprise. An hour after that first appearance of the while smoke, the slight and slightly trembling figure of Cardinal Jean-Louis Tauran came to the balcony.

Cardinal Tauran, who has Parkinson's disease, delivered the famous declaration "habemus papam", we have a Pope.

The crowd was silent as he read out, in Latin, the name of the man singled by his fellow Cardinals, ending with the name he had chosen to take as Pope, Francis.

Now the crowd had the news for which they had waited. But was the cheering that little bit more muted? Were they asking each other, "Bergoglio, which one is he?".

On our rooftop that was the question we were asking. He wasn't considered a frontrunner but neither was he a complete outsider.

The new Pope, when he appeared a few minutes later, faced the crowd with what seemed an expression of calm and serenity.

When he spoke, his words were those of a pastor to his people. Pray for me, he asked and they did.

Once again the great crowd fell silent and then softly began to recite the rosary.

Gazing down from his balcony high above the entrance to Saint Peter's Basilica, this modest South American prelate cannot but be aware of the enormity of the task he has undertaken.

Looking beyond the heads of the cheering crowd, out beyond the Vatican and the city of Rome, he must see a Church in period of deep crisis.

Beset on all sides by difficulties and controversies, Catholics will look to Pope Francis for vision, leadership and inspiration.

His first challenge will be to know where to start: to reform the entrenched Vatican bureaucracy and its various departments, including the highly secretive Vatican bank; to finally come to grips with the issue of clerical child abuse; to find a convincing answer to the increasing secularisation in many developed societies.

As the crowd dispersed last night and the cheering faded, those pressing issues loomed into view once again.

Partly but only temporarily obscured by the elation that greeted Pope Francis' election they now crowd in on the new pontiff as he embarks on what may be the greatest challenge yet of the more than 50-year long ministry.