Pope Francis presided over the Palm Sunday Mass in St Peter's Square on Sunday, a day after he was released from a Rome hospital following a bronchitis infection.
Palm Sunday marks the beginning of Holy Week, which culminates on Easter Sunday, the most important holiday in the Christian faith.
"I thank you for your participation and also for your prayers, which intensified during these past days. Thank you!" Francis said to the crowd of some 30,000 gathered at St. Peter's Square.
The hospital visit had raised questions about the health of the 86-year-old pontiff and whether he would be fit enough to lead the numerous ceremonies during Holy Week.
Francis led the Mass while sitting, an arrangement that had already been adopted due to his inability to stand for long periods of time.
He called on people not to ignore those experiencing great suffering and solitude.
"Today their numbers are legion," he said. "Entire peoples are exploited and abandoned; the poor live on our streets and we look the other way. Migrants are no longer faces but numbers. Prisoners are disowned. People written off as problems."
What is Palm Sunday?
The celebrations kicked off on Sunday as a procession of scores of priests and red-robed cardinals walked through the square. Some 30,000 people stood by holding palm fronds and olive branches.
The pope followed in the pope mobile, waving at the crowds but looking serious.
For Christians, Palm Sunday marks the arrival of Jesus in Jerusalem ahead of his crucifixion on Good Friday and resurrection on Easter Sunday.
Pope Francis' health issues
The pontiff was taken to hospital last Wednesday after complaining of breathing difficulties.
He was administered a course of antibiotics intravenously and rapidly recovered, leaving the hospital on Saturday, quipping to reporters and well-wishers "I'm still alive!"
It was his second hospitalization since 2021 when he underwent colon surgery.
He has also had problems with his knees, forcing him to use a wheelchair and walking stick.
Francis marked his 10-year anniversary as the head of the 1.3 billion-strong Catholic Church in March.
But his health issues have led some to wonder whether he will step down from the role rather than hold it until his death. Although he has brought up the possibility before, he said last month that he has no plans to quit.
ab/sms (AFP, AP, Reuters)