“Happy Birthday Holy Father!” That was the rousing chorus serenading Pope Benedict XVI April 17 as he concluded this year’s Palm Sunday ceremonies in St Peters Square. The Pope, who turned 84 Saturday, had earlier used his Sunday sermon to warn the world that advances in technology won’t necessarily save mankind from future catastrophes.

 “With the increase of our abilities there has been an increase not only of good. Our possibilities for evil have increased and appear like menacing storms above history,” he said. “Our limitations have also remained: we need but think of the disasters which have caused so much suffering for humanity in recent months.”

The Palm Sunday service recalls the triumphal entry of Jesus Christ into Jerusalem nearly 2000 years ago. In imitation of those events, today’s papal ceremonies began with a solemn procession of bishops, cardinals and the Holy Father himself carrying palm leaves. This is how the Jerusalem crowd welcomed Jesus himself.

Over 50,000 pilgrims basking beneath the Roman sun joined the churchmen in waving palms.

Today’s events also mark the start of Holy Week, the most sacred time of the year for Christians. Over the next seven days the Catholic Church will recall the death, crucifixion and resurrection of Jesus Christ, culminating in Easter Sunday.

Pope Benedict concluded his sermon by highlighting the life and work of St. Augustine of Hippo. The fifth century Christian philosopher, he suggested, had outlined the best solution to the question of human evil.

“(H)e should have despaired of himself and human existence had he not found the One who accomplishes what we of ourselves cannot accomplish; the One who raises us up to the heights of God in spite of our wretchedness: Jesus Christ who from God came down to us and, in his crucified love, takes us by the hand and lifts us on high.”