Mac Aodhagáin, Giolla na Naomh (d. 1309), is the first member of the family of Mac Aodhagáin (MacEgan) to be mentioned in Irish records in a legal context. His death is recorded in the Annals of Connacht, where he is described as ‘the chief legal expert of Connacht and a well versed master in every other art’. Other annals imply even greater eminence: the Annals of Ulster describe him as ‘the chief expert of Connacht and of Ireland’. He also features in the genealogies of the MacEgan family, where he is described as ardollamh i mbreitheamhnas Féineachais ‘high expert in Irish law’.
Nothing is known of his mother and no information survives concerning his father, Donnshléibhe Mac Aodhagáin, but it is probable that he also was a lawyer, as the MacEgans seem to have taken up the legal profession at least as early as the beginning of the thirteenth century. The family originated as secular tributaries of the Ó Ceallaigh lords of Uí Mhaine, and dominated the field of native law till the collapse of the Gaelic order at the end of the sixteenth century. Members of the family are recorded as having acted as judges or ‘brehons’ (breitheamhain) for most of the great families of western and central Ireland of both Gaelic and Anglo-Norman stock. Giolla na Naomh was chief brehon to the king of Connacht, Aodh mac Eoghain Ó Conchobhair. He was killed along with his lord and other dignitaries during the course of a feud among the Uí Chonchobhair. It seems that his immediate family moved south after his death. One of his sons, Fiachra, took holy orders and became dean of Cluain Fearta (Clonfert, Co. Galway). Another son, Conchobhar, was ancestor of the branch of the MacEgans which for many generations provided brehons for the great families of Iarmhumha (Ormond). Nothing appears to be known about a third son, Cairbre.
Three important legal compositions are attributed to Giolla na Naomh. His ‘Address to a student of law’ consists of a poem of twenty-five stanzas, which summarises the educational requirements of a law-student. In the concluding stanza Giolla na Naomh describes himself as ‘physician of the schools’ – presumably referring to the close attention which he devotes to the students under his care. He predicts that his fame will live on after his death, and boasts that he has acquired a secure holding of land. He stresses the importance of a detailed knowledge of the law texts, but warns that they should not be viewed uncritically, and that only what is of value and worth in them should be followed. The student is expected not to limit his studies to the law texts but to cultivate the art of poetry, to gain expertise in the genealogies, and to learn the wisdom texts attributed to the sages Fíothal, Cormac, and Morann. He should maintain his integrity when he qualifies as a judge, and refuse to deliver a one-sided judgment in exchange for a bribe.
Giolla na Naomh is also credited with authorship of a poem of seventy-eight stanzas summarising the main Old Irish law text on distraint. This highly technical work displays his profound knowledge of the law texts, and also confirms his association with the province of Connacht and the Ó Conchobhair family.
The third text attributed to Giolla na Naomh is very different from the other two. It is in prose, and presents a simplified version of the Old Irish law-texts in contemporary language. This ‘Treatise’ (Tráchtadh) covers some of the main topics of the law-texts, including murder, injury, theft, insult, offences against women, animal trespass, lost property, contracts, pledges, sureties, loans, and deposits. In his treatment of these topics, Giolla na Naomh generally follows the Old Irish law texts fairly closely. He also bases portions of his ‘Treatise’ on Middle Irish legal commentaries, which themselves derive largely from the Old Irish texts. In addition, there is a good deal of material that cannot be traced to either of these sources. Some of it may come from law texts that have not survived. However, it is likely that Giolla na Naomh also contributed legal material of his own composition to the ‘Treatise’. His practical treatment of topics such as contracts and injuries indicates that he had wide experience of legal practice, as well as being an accomplished academic lawyer. On occasion he records in the ‘Treatise’ that his own opinion differs from that of the law texts.
Giolla na Naomh's up-to-date approach is further illustrated by his use in the ‘Treatise’ of legal terminology of Anglo-Norman origin. For example, he uses the word baránta ‘guarantor, surety’ (a borrowing from Anglo-Norman warantie) beside urradh, a native term with the same meaning. He likewise calls the royal steward seiniscal (from Anglo-Norman seneschal) or uses the earlier terms maor or rechtaire. His terminology also reflects the influence of Anglo-Norman inheritance customs. On two occasions he employs the term sínfhogas, an otherwise unattested compound of the Anglo-Norman loan sín ‘assign, appointed heir’, and Irish fogas ‘kinsman’. As well as innovative vocabulary, the ‘Treatise’ also contains legal concepts that differ from those of traditional Irish law. Thus, he gives a lower body-fine (éiric) to the bastard son of a king or chieftain than to a legitimate son. In early Irish law, all recognised sons – except those by a slave woman – had equal legal standing.
In conclusion, Giolla na Naomh stands out as a very significant figure in the history of Irish law. He was clearly much admired in his own lifetime, and helped to establish the MacEgans as the most influential legal family in Gaelic Ireland. He was also an innovator, in that he composed three substantial works designed to summarise and explain the contents of the Old Irish law texts.