Donngus Ua hAingliu also known as Donatus and Donat O'Haingly, was the third Bishop of Dublin

Archbishop of Dublin

The Archbishop of Dublin may refer to:* Archbishop of Dublin – an article which lists of pre- and post-Reformation archbishops.* Archbishop of Dublin – the title of the senior cleric who presides over the Roman Catholic Archdiocese of Dublin....

. Donngus was elevated to the see of Dublin following bishop Gilla Pátraic

Gilla Pátraic

Gilla Patráic , also known as Patricius, was the second Bishop of Dublin. Gilla Patráic was elevated to the see of Dublin following bishop Dúnáns death in 1074, He was consecrated by Lanfranc, Archbishop of Canterbury...

s death in 1084. He was consecrated by Lanfranc

Lanfranc

Lanfranc was Archbishop of Canterbury, and a Lombard by birth.-Early life:Lanfranc was born in the early years of the 11th century at Pavia, where later tradition held that his father, Hanbald, held a rank broadly equivalent to magistrate...

, Archbishop of Canterbury

Archbishop of Canterbury

The Archbishop of Canterbury is the senior bishop and principal leader of the Church of England, the symbolic head of the worldwide Anglican Communion, and the diocesan bishop of the Diocese of Canterbury. In his role as head of the Anglican Communion, the archbishop leads the third largest group...

 in 1085 at "the request of the king, clergy, and people of Ireland" (Acta Lanfranci)

Donngus had been trained as a monk at Christ Church in Canterbury. Like his predecessor Gilla Pátraic he returned from his consecration with letters of exhortation from Lanfranc to the kings and clergy of Ireland. According to a subsequent letter from Lanfranc's successor in Canterbury, Anselm

Anselm of Canterbury

Anselm of Canterbury , also called of Aosta for his birthplace, and of Bec for his home monastery, was a Benedictine monk, a philosopher, and a prelate of the church who held the office of Archbishop of Canterbury from 1093 to 1109...

, Lanfranc had also given books, vestments and ornaments for the church in Dublin to Donngus.

In his obit in the Annals of Ulster

Annals of Ulster

The Annals of Ulster are annals of medieval Ireland. The entries span the years between AD 431 to AD 1540. The entries up to AD 1489 were compiled in the late 15th century by the scribe Ruaidhrí Ó Luinín, under his patron Cathal Óg Mac Maghnusa on the island of Belle Isle on Lough Erne in the...

 Donngus is described as "bishop of Áth Cliath" (espoc Atha Cliath) just like Gilla Pátraic, while the first recorded bishop in Dublin, Dúnán

Donat, Bishop of Dublin

Dúnán was the first bishop of Dublin, appointed under Dublin's Hiberno-Norse kings. He is known also as Donatus or Donat. The diocese was put on a regular basis, in 1028, at the request of Sigtrygg Silkbeard...

, had been titled "chief bishop of the foreigners" (ardespoc Gall).