BBC News recalls the event by republishing this story which first appeared on September 29, 1979:
He was loudly applauded at Drogheda when he said, in a direct address to the consciences of both terrorists and politicians: "I appeal to you in language of passionate pleading.
"On my knees I beg you to turn away from the paths of violence and return to the ways of peace."
He continued: "To Catholics, to Protestants, my message is peace and love. May no Irish Protestant think the Pope is an enemy, a danger or a threat."
Read more: 1979: Pope calls for peace in Ireland