Brehon Laws, the name given by the English to the system of jurisprudence which prevailed among the native Irish from an early period till towards the middle of the 17th century. The breitheamhuin (pronounced brei-hoo-in or brehon), from whom the laws have received their name, are supposed to have been hereditary judges, who administered justice among the members of their tribe seated in the open air, upon a few sods, on a hill or rising ground. The poet Spenser in his View of the State of Ireland, written in 1596, describes the Brehon Laws as 'a rule of right unwritten, but delivered by tradition from one to another, in which oftentimes there appeareth great share of equity in determining the right between party and party, but in many things repugning quite both to God's law and man's: as, for example, in the case of murder, the brehon—i.e. their judge—will compound between the murderer and the friends of the party murdered, which prosecute the action, that the malefactor shall give unto them, or to the child or wife of him that is slain, a recompense, which they call an eric; by which vile law of theirs many murders amongst them are made up and smothered.' Spenser was ignorant that pecuniary compensation for manslaughter had obtained in the ancient laws as well of England as of most European nations. He was mistaken, too, in believing that the Brehon Laws were an unwritten code. Among numerous portions of manuscript collections of the Brehon Laws still existing in public and private libraries may be mentioned those of the Royal Irish Academy, Trinity College, Dublin, the British Museum, and the Bodleian. These manuscripts are regarded as varying in date from the early part of the 14th to the close of the 16th century. For the laws themselves a much higher antiquity is claimed. Portions of them are referred to in compilations of the 10th century, and it may be, as has been suggested, that the redaction of them in their present form was due to Cormac Mac Cuilleanain (killed 903 A.D.), king and archbishop of Cashel, a man of great learning and energy; but of this there is no actual record. The recension of the code, known as the Seanchus Mor, is traditionally ascribed to St Patrick (5th century), who is said to have expunged from the laws all institutions savouring of heathenism; and here again we are met with references to written laws dating from the reign of Cormac Mac Art (3d century). The language in which the Brehon Laws are composed is Ancient Irish, and though in general intelligible enough, it is sometimes rendered obscure by technical and obsolete legal terms, of which the exact meaning is uncertain.
The form of society presupposed by the laws is such as is known to have existed in Ireland in the earliest historic times. The basis of it is the tribe, and the principal occupation is the pasturage of cattle or the tillage of the soil. The whole community is arranged in a graded system of monarchs, provincial kings, chiefs, proprietors, clansmen, and serfs of an alien race. The land seems to have been divided into two parts, one as common pasture ground, the other portioned out among the chiefs and other tribal dignitaries, with the poorer clansmen and serfs holding as tenants under a proprietor. The use of coined money is apparently unknown, as fines and valuations are represented in terms of so many head of cattle.
Every part of life comes within the range of the law; there are regulations for the fostering of the children of the nobles, for their food and education, for their dress and its quality, along with ordinances regulating the holding of courts and the giving of evidence. And in the midst of all this, there survive the remains of a pagan past not yet eradicated by Christianity, such as the laws of marriage and magical ordeals. In 1852 a Royal Commission was appointed 'to direct, superintend, and carry into effect the transcription and translation of the ancient laws of Ireland, and the preparation of the same for publication.' The commissioners entrusted the transcription and translation of the Brehon Laws to the two most eminent Irish scholars—Dr John O'Donovan, professor of Celtic in the Queen's College at Belfast, and Eugene O'Curry, professor of Irish Archæology in the Roman Catholic university of Ireland. Four volumes have appeared under various editors—the last in 1885—under the title of Ancient Laws and Institutes of Ireland. Along with the Irish text, an English translation is given, accompanied with preliminary dissertations and indexes, and they give a vivid and characteristic picture of the polity and social life of a Celtic people.