Irish Family Research Discover the secrets of your ancestors’ past Brendan Mullins Genealogist

    Gaelic Genealogical Sources

      MacLysaght’s Surname and Family Publications                                                                                                                                                                      To locate the roots of Gaelic septs, one must explore manuscripts, annals and genealogies from the 17th century and earlier. However, the best place to commence a search is with the published work on surnames1 and Irish families2 by Edward MacLysaght. He was a leading authority in this field, and these publications are ‘The Surnames of Ireland’, ‘Irish Families’ and ‘More Irish Families’. They give the Irish form of the name and its derivation, the various septs that arose, and their localities. The use of surnames in Ireland began mainly in the 11th century, although some, like Ó Neill and Ó Cléirigh, began much sooner. In most of the earlier instances, Mac was prefixed to the father’s Christian name and Ó to that of a grandfather or earlier ancestor. It should also be noted that there are many surnames, with several septs, descended from ancestors that are not related.

      The Great Book of Irish Genealogies                                                                                                                                     There are many manuscripts worth researching and probably the best and most famous one to commence with is ‘The Great Book of Irish Genealogies’ (Leabhar Mór na nGenealach) compiled and written in Galway, around 1649-1650, by Dubhaltacht Mac Fhirbhishigh, who was from Lacken in Co. Sligo, and translated into English by Nollaig Ó Muraíle. The publisher is De Búrca Rare Books, Dublin. There are five large volumes and by researching the index, one will find the locations of pedigrees required. With by far the largest collection of all, this manuscript is long recognised as the most important source for Irish Genealogy and pre 17th century Irish history. It was only in recent years that the entire contents were printed in transcript. Probably the best place to commence is by researching the Index of names. However, great care should be taken when locating a first name, that it is the correct person, as many names are frequently repeated, or in some cases, omitted. In fact, at times, a few generations may be omitted. The comparison of different manuscripts can occasionally help solve this. The Great Book of Irish Genealogies’ can be found in the National Library of Ireland, the UCD Library, many more of the larger libraries and also on the internet.


      The Fiants of the Tudor Soverignty                                                                                                                                     For dates and various pieces of interesting information on the septs being researched from the late 16th century, ‘The Irish Fiants of the Tudor Sovereigns During the Reigns of Henry VIII, Edward VI, Philip and Mary, and Elizabeth I’ can be of a great assistance, showing how the English throne won people over with their ‘Surrender and Re-grant’ policy. They were then granted titles for their co-operation. They are in four volumes. The original fiants were destroyed during the 1922 Civil War, but fortunately, they had been calendared, indexed and published and contain a well detailed account of the originals. A greater understanding of the events of the period can be obtained from these. For this period also there is ‘The Records of the English Colonisation of Ireland, from Norman Times onwards’, and ‘The Calendar of State Papers (Ireland)’ to research.

      The History of Ireland and Local History Publications                                                                                                                                     To bring the periods being researched into focus, the various history books available can be of great assistance. They give a better understanding of the events then, such as the advance of the Normans across the country, their encroachment and eventual conquest of different territories and often contain maps and illustrations. Two of these publications are ‘A New History of Ireland, Vol. II, Medieval Ireland, 1169 – 1534 A.D.’ by Art Cosgrove and ‘The Course of Irish History’ by T. W. Moody and F. W. Martin. For the areas being researched, local histories can be of even greater assistance, especially where they give reference to their sources. Two excellent examples of these are ‘The History of Mayo’ by H. T. Knox and ‘The History of Sligo’ by W. G. Wood-Martin. Both of these give an excellent account of the various families within their county.  

 1  Edward MacLysaght, The Surnames of Ireland, Sixth Edition, 2007, First Published 1985, Irish Academic Press, Dublin 4.


2 Edward MacLysaght, Irish Families, Fourth Edition 1991, First Published 1957, Irish Academic Press, D 4 and More Irish Families, First Edition 1982, Irish Academic Press, D 4.

      The Annals of the Four Masters                                                                                                                                     This should then be followed by ‘The Annals of the Four Masters’, also known as ‘The Annals of the Kingdom of Ireland from the Earliest Times to 1616’, compiled by the Franciscan Brother Micheál Ó Cléirigh from Tir Conaill, Co. Donegal, and three assistants. These were Fearfeasa ÓMaolchonaire from Roscommon, Cúcoigcríche Ó Dubhgennáin from Leitrim and Cúcoigcriche Ó Cléirigh, a distant cousin. Two others helped for a short period. Brother Micheál studied at the Franciscan College in Louvain, France, which was then headed by another Donegal scholar named Hugh Ward. He was first returned to Ireland to gather information on the Irish Saints, but it appears that as he located vast amounts of historical material, it was decided to compile these Annals and they completed the work in 1636, just a few years before the destruction of the old Gaelic organisation of Irish society3. This manuscript contains dates, which can then be added to the individuals identified from the first manuscript, however the same precautions concerning missing generations, should be taken. The earlier items up to the eleventh century, which contain the Old Testament, ancient legends and stories with some truth, but to a large extent, mythological, can mostly be ignored, as the standard of reliability decreases the further back one goes. The same applies to the dates given, but from the early 11th century they are believed to be mostly correct or very close. It is also known that some of the older manuscripts, such as the ‘Book of Lecan’, were used in the research. Special attention should be given to the footnotes, for additional information. Depending on the sept, time and location being researched, further information can be located in the many other manuscripts, such as ‘The Book of Munster’, ‘The Annals of Connaught’, ‘The O’Clery Book of Genealogies’, ‘The Book of the O’Hara’s’, and other genealogies compiled by the larger families.

      The Book of O’Hara/Leabhar Uí Eadhra                                                                                                                                     This book was created by Irish bardic poets near the end of the 16th Century. It is written in old Irish so it can be difficult to translate and it gives very few dates or years, but working alongside the information gathered from ‘The Annals of the Four Masters’, additional pieces can be found. It is available on the Internet4.

      The Genealogies, Tribes and Customs of Hy-Fiachrach                                                                                                                                     Another excellent source, for families from the west of Ireland, is ‘The Genealogies, Tribes and Customs of Hy-Fiachrach’ which was compiled from the Genealogical Manuscript of Duald MacFirbis that was written about 1666. It was translated by John O’Donovan, who was born in Co. Kilkenny in 1809, and first printed in 18445. Much of the information comes from The Book of Lecan which dates from about 1416 and contains a large amount of information on the Ui Fiachrach territory of west Sligo and part of Mayo6. It was also known as the ‘Book of Ó Dowda’, - the most prominent family of the area, and it contains pedigrees of the main families. Prior to writing this book, O’Donovan wrote ‘The Genealogies, Tribes and Customs of Hy-Many’, which is about an area known as O’Kelly country, in East Galway and South Roscommon. He also wrote other similar books.  

     The Internet                                                                                                                                     Much of the information in the various manuscripts and on the various septs in separate items, can be located on the internet. One example of this is ‘Letters on the manuscript materials of Ancient Irish History’7 by Eugene Ó Curry. It can also supply further information on books and manuscripts to research in the Libraries and Archives. There is a large selection of printed material related to different septs or parts of the country, and one is sure to locate some material, whether small or large, on the septs one is researching. Some of these may even be found on Google Books, or similar. However, also on the internet there are many websites compiled by amateurs and these must be read with caution, or avoided.

Great Book of Irish Genealogists The Great Book of Irish Genealogists Annals of the 4 Masters The Annals of the Four Masters also known as The Annals of the Kingdom of Ireland Signatures of 4 Masters The Signatures of the Four Masters Two Sample Surnames are attached:-

 3  Michael Slavin, The Ancient Books of Ireland, Published in 2005 for the National Museum of Ireland, Printed by Wolfhound Press, Dublin 2, chapter 10, pages 172-186.


4 Author Unknown, The Book of O’Hara/Leabhar Í Eadhra, 16th Century, http:/ 11-3-2010

 5  John O’Donovan, The Genealogies, Tribes and Customs of Hy-Fiachrach, Published in 1884 for the Irish Archaeological Society, Dublin from the Gen. Ms. Of Duald MacFirbis, Printed by The Univ. Press, Dublin.


6 Slavin, The Ancient Books of Ireland, 2005,  pp 62-67

 7  Eugene Ó Curry, Letters on the manuscript materials of Ancient Irish History, 2 Vols. 1861 Dublin, National Library of Ireland, Dublin

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