Pope Francis has inaugurated his papacy at a Mass in Rome, calling on global leaders and all the people of the world to defend the poor and the weak.
The pope delighted the crowd when he arrived in an open-top popemobile and drove through the crowd, at one point getting out to kiss an ill or disabled man.
Up to 200,000 people attended the Mass in St Peter's Square in the Vatican.
His homily focused on protection - of the environment, children, the elderly and those in need, who he said were "often the last we think about".
Pope Francis, formerly Argentine Cardinal Jorge Mario Bergoglio and now the first pontiff from the Americas, has since his election called for a "Church for the poor" and has struck an informal and spontaneous tone.
His chosen name, Francis, honours St Francis of Assisi, the 13th-Century son of an aristocrat who spurned a life of luxury to live with and for the poor.
Pope Francis' homily at the Mass began by focusing on Joseph and his role as protector - of Mary, Jesus and the Church.