Áed Ua Crimthainn also called Áed mac Crimthainn, was abbot

Abbot

The word abbot, meaning father, is a title given to the head of a monastery in various traditions, including Christianity. The office may also be given as an honorary title to a clergyman who is not actually the head of a monastery...

 and coarb of Terryglass

Terryglass

Terryglass is a village in North Tipperary, Ireland. The village is located on the R493 regional road on the north-eastern shore of Lough Derg near where the River Shannon enters the Lough. It is a civil parish in the historical barony of Ormond Lower. It is also an Ecclesiastical parish in the...

 (Tir dá Glas), near Lough Derg in County Tipperary

County Tipperary

County Tipperary is a county of Ireland. It is located in the province of Munster and is named after the town of Tipperary. The area of the county does not have a single local authority; local government is split between two authorities. In North Tipperary, part of the Mid-West Region, local...

, Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

. He was the principal scribe of the Book of Leinster

Book of Leinster

The Book of Leinster , is a medieval Irish manuscript compiled ca. 1160 and now kept in Trinity College, Dublin, under the shelfmark MS H 2.18...

 (in Irish

Irish language

Irish , also known as Irish Gaelic, is a Goidelic language of the Indo-European language family, originating in Ireland and historically spoken by the Irish people. Irish is now spoken as a first language by a minority of Irish people, as well as being a second language of a larger proportion of...

 Lebar na Núachongbhála, the Book of Oughaval

Oughaval (County Laois)

Oughaval , County Laois, Ireland, sometimes called Oakvale, is a townland within the present day parish of Stradbally and is the site of a sixth century monastic settlement.-Monastery:...

, an important Middle Irish medieval illuminated manuscript

Illuminated manuscript

An illuminated manuscript is a manuscript in which the text is supplemented by the addition of decoration, such as decorated initials, borders and miniature illustrations...

, and is also believed to have been its sole compiler.

Áed signed himself Áed Ua Crimthainn.

Life and work

Áed was a scholar and a descendant of an old ecclesiastical family of County Laois

County Laois

County Laois is a county in Ireland. It is part of the Midlands Region and is also located in the province of Leinster. It was formerly known as Queen's County until the establishment of the Irish Free State in 1922. The county's name was formerly spelt as Laoighis and Leix. Laois County Council...

 who were the comarbai (heirs) of Colum moccu Loigse, the 6th century founder of the religious house of Terryglass and a friend of Colum Cille

Columba

Saint Columba —also known as Colum Cille , Colm Cille , Calum Cille and Kolban or Kolbjørn —was a Gaelic Irish missionary monk who propagated Christianity among the Picts during the Early Medieval Period...

. He was the temporal, if not the spiritual, head of Terryglass, succeeding Finn mac maic Chélechair Ui Cheinnéidig, who died in 1152. It seems that Áed himself had no successor and was the last coarb, as Terryglass was burned down in 1164 and was then dissolved by reforms later in the century.

Áed was a friend of Finn mac Gussáin Ua Gormáin, bishop of Kildare

Bishop of Kildare

The Bishop of Kildare was an episcopal title which took its name after the town of Kildare in County Kildare, Ireland. The title is no longer in use by any of the main Christian churches having been united with other bishoprics. In the Roman Catholic Church, the title has been merged with that of...

 and abbot of Newry

Newry

Newry is a city in Northern Ireland. The River Clanrye, which runs through the city, formed the historic border between County Armagh and County Down. It is from Belfast and from Dublin. Newry had a population of 27,433 at the 2001 Census, while Newry and Mourne Council Area had a population...

, who sometimes collaborated with him. Both Finn and Gilla na Náem Úa Duinn assisted Áed with compiling the Book of Leinster.

According to a note in the Book of Leinster "Áed Ua Crimthainn wrote the book and collected it from many books". It is a literary compendium of stories, poetry, and history, and it appears from annals

Annals

Annals are a concise form of historical representation which record events chronologically, year by year. The Oxford English Dictionary defines annals as "a narrative of events written year by year"...

 included in it that it was written between 1151 and 1201, although largely completed by the 1160s. The last entry in the manuscript in Áed's hand which can be dated appears to belong to the year 1166. Gerald of Wales saw the book when he accompanied his cousin Strongbow

Richard de Clare, 2nd Earl of Pembroke

Richard de Clare, 2nd Earl of Pembroke , Lord of Leinster, Justiciar of Ireland . Like his father, he was also commonly known as Strongbow...

 on his invasion of Ireland

Norman Invasion of Ireland

The Norman invasion of Ireland was a two-stage process, which began on 1 May 1169 when a force of loosely associated Norman knights landed near Bannow, County Wexford...

 and said of its illuminations that they were "the work of Angels".

Áed was probably the court historian of Diarmait Mac Murchada. In the Book of Leinster he was apparently the first scholar to create the concept of the rí Érenn co fressabra, the "king of Ireland with opposition", later more widely adopted. This described Diarmait's ambitions and the achievements of his great-grandfather Diarmait mac Maíl na mBó

Diarmait mac Mail na mBo

Diarmait mac Maíl na mBó was King of Leinster, and also High King of Ireland .He was one of the most important and significant Kings in Ireland in the pre-Norman era...

. Áed's description of the period between the death of Máel Sechnaill mac Domnaill

Máel Sechnaill mac Domnaill

Máel Sechnaill mac Domnaill , also called Máel Sechnaill Mór, Máel Sechnaill II, anglicized Malachy II, was King of Mide and High King of Ireland...

 and the rise of Diarmait mac Maíl na mBó was misread by Conall Macgeoghegan when he compiled the so-called Annals of Clonmacnoise

Annals of Clonmacnoise

The Annals of Clonmacnoise are an early 17th-century Early Modern English translation of a lost Irish chronicle, which covered events in Ireland from pre-history to A.D. 1408...

in the 17th century, leading to the inclusion of poet Cuán Ua Lothcháin and abbot Corcrán Clérech in some old lists of High Kings of Ireland.

A letter from Bishop Finn to Áed was copied into the Book of Leinster, at folio 206, by one of the other hands of the manuscript. This has been called the oldest surviving personal letter to have been written in Ireland, although this ignores earlier correspondence between Irish bishops and the archbishops of Canterbury. The letter reads:
Áed respected Irish tradition, even when it offended his religious beliefs or his educated sense of reason. However, at the end of the Book of Leinster, the writer added this reservation: