Thousands of people led by Archbishop Eamon Martin have climbed Croagh Patrick in Co Mayo.
The annual Reek Sunday event attracts pilgrims from across Ireland each year.
St Patrick is believed to have spent 40 days and 40 nights fasting on the summit of the famous mountain in the year 441.
On Sunday, the Archbishop of Armagh Eamon Martin celebrated Mass in a small church at the top of the 765-metre high mountain.
This year's pilgrimage is dedicated to vocations to the priesthood.
In his homily, Archbishop Martin said: "Croagh Patrick, represents the rock from which we, the people of Ireland, were hewn.
"Today's pilgrimage links our past, present and future and it continues to nurture the spiritual memory and identity of this country."
Archbishop Martin called on St Patrick to intercede for Ireland.
"Today from this holy place, ‘near the western sea’, I call out once more to our patron saint to intercede for Ireland, to come and walk once more among us," he said
"To rekindle in us the memory of the rock from which we were hewn, and to help us rediscover that wisdom for which he himself prayed - to be able to discern good from evil - for ourselves personally, for our families, our communities, for Ireland,"
Father Charlie McDonnell, Administrator of the parish of Westport, said the "church needs vocations to the priesthood like never before".
"No doubt it is a challenging time to minister as a priest, but in my role I find that serving the people of God in today's counter-cultural environment is nothing short of a faith-enriching experience," he told RTE.
