Imhar was in sympathy with the aims of those who sought to reform the Irish church, and it was probably through his influence that Malachy became imbued with their principles.

With the consent of Cellach and Imar, he went to study under Máel Ísu Ua hAinmere (Malchus, first Bishop of the Norse city of Waterford), who had by this time retired from the archbishopric of Cashel and was settled at Lismore.

Cellach, as coarb of Patrick, and consecrated bishop, had been able to organize the diocese of Armagh in accordance with the Rathbreasail plan.

On the death of Celsus (who was buried at Lismore in 1129), Malachy was appointed Archbishop of Armagh, in 1132, which dignity he accepted with great reluctance.

Owing to intrigues, he was unable to take possession of his See for two years; even then he had to purchase the Bachal Isu (Staff of Jesus) from Niall, the usurping lay-primate.

During three years at Armagh, as Bernard of Clairvaux writes, Malachy restored the discipline of the church, grown lax during the intruded rule of a series of lay-abbots, and had the Roman Liturgy adopted.

[3] Bernard continues: Having extirpated barbarism and re-established Christian morals, and seeing all things tranquil, Malachy began to think of his own peace.

He petitioned Pope Innocent II for pallia for the Sees of Armagh and Cashel, and was appointed legate for Ireland.

On his return visit to Clairvaux, he obtained five monks for a foundation in Ireland, under Christian, an Irishman, as superior: thus arose the great Abbey of Mellifont in 1142.

Malachy set out on a second journey to Rome in 1148, but on arriving at Clairvaux, he fell sick and died in the arms of Bernard, on 2 November 1148.

Charles Borromeo praised Malachy for attending to the needy, bringing the holy sacraments to all alike and renewing the fervour of the people in receiving them.

He founded a large number of churches and colleges, as many as forty-four in all, endowed them with land and rents and so allowed many men of religion to serve God devotedly, although he hardly retained enough for himself to live on."

However, the Irish Famine broke out and the grand plans for Saint Malachy's Cathedral were shelved to divert funds to the needy.

[11] James Weiss, a professor of church history at Boston College, has stated: "It is widely thought ... given who the author was and his relationship, [that the prophecies] were published to establish the case for election of one particular cardinal.

"[12] Thomas Groome, chair of the Department of Religious Education and Pastoral Ministry at Boston College, has a similar notion: "For myself – and even as a native Irishman – the 'Prophecies of St. Malachy' are a grand old fun tale that have about as much reliability as the morning horoscope".