The Pope has begged for God's forgiveness for the "open wound" of church abuse in Ireland as he called for "firm and decisive" action to secure "truth and justice".
The Pope is in Co Mayo ahead of his visit to the famous Holy shrine.
Around 100 schoolchildren from Co Mayo were awaiting the arrival of Pope Francis.
Four local schools were there to greet the pontiff as he landed in heavy rain for the start of his second day visit to Ireland. They waved Vatican and Mayo flags.
In August 1879, 15 people said they saw an apparition in Knock of the Virgin Mary, St Joseph, St John the Evangelist and a lamb.