Mervyn Archdall, Irish antiquarian and clergyman of the Church of Ireland, is born on April 22, 1723, in Dublin, elder son among two sons and three daughters of William Archdall, goldsmith, and his wife Henrietta, a widow who is the daughter of Henry Gonne, curate of Finglas. His father is Dublin assay master from 1736 until his death in 1751, and is a member of the gentry family from Castle Archdale, County Fermanagh.

Archdall is educated by Dr. Keenane, and enters Trinity College Dublin (TCD) in 1739. He graduates with a Bachelor of Arts (BA) in 1744 and a Master of Arts (MA) in 1747, and is ordained in the Church of Ireland. He is curate of Howth from 1750 to 1753, and of Kilgobbin and Taney, also in Dublin, from 1753 to 1758, rector of Nathlash in the diocese of Cloyne from 1749 to 1758, and from 1756 domestic chaplain to Richard Pococke, Bishop of Ossory. In 1761 Pococke gives Archdall the livings of Agharney and Attanagh in Ossory which he holds until 1786, when he becomes rector of Slane in the Diocese of Meath. He is also prebendary of Cloneamary from 1762 to 1764 and of Mayne from 1764 to 1772, both in Ossory.

Archdall is interested, almost from his student days, in ancient history and antiquities, and for forty years he gathers material for a work similar to an earlier compilation, William Dugdale‘s Monasticon Anglicanum. He intends to publish two or more large folio volumes, but after Pococke’s death has no sponsor and has to pay for its publication himself causing him to cut back the scale of the project. Monasticon Hibernicum appears in 1786 as a quarto volume, though still of over 800 pages. Archdall attempts encyclopaedic coverage of the history of Ireland’s pre-reformation monasteries and abbeys. The work is ground-breaking and ambitious, though marred by mistakes and inadequacies. He receives help from friends, including scholars such as Pococke and Edward Ledwich, and with them and others is a founder member of the Royal Irish Academy (RIA) in 1786.

In 1789, Archdall publishes his second important work, a new edition of The Peerage of Ireland by John Lodge. Lodge’s original work in four volumes is expanded by Archdall into seven octavos, adding a good deal of material from his own research to update the genealogies, as well as incorporating manuscript additions unpublished by the original author. These had been left in a cipher or in a private form of shorthand which could not be decoded by any contemporary expert in Dublin, and Archdall is just about to abandon the attempt to read them when his second wife works on it and discovers the key.

Archdall’s first wife, Sarah Colles or Collis, whom he marries in Dublin on July 30, 1747, is said to have been a relative of Thomas Prior, though she may also – or instead – have been connected in some way to Pococke. The bishop is known to have educated Christopher Colles (1739–1816), who becomes an important engineer and entrepreneur in the United States. They have two sons and a daughter, the elder son dying young. Sarah dies on May 28, 1782. Archdall marries his second wife, Abigail Young, on November 25, 1782.

Archdall’s works are still of interest to historians and genealogists, and surviving copies are valuable collectors’ items. In an apologia in his preface to the Peerage he notes, “I have left that inaccurate which could not be exact, and that imperfect which cannot be completed.” He dies suddenly on August 6, 1791, and is buried in Slane churchyard.

(From: “Archdall, Mervyn” by Linde Lunney, Dictionary of Irish Biography, http://www.dib.ie, October 2009)