As explained before, the Brehon Code, which St. Patrick found in Ireland, owed its existence mainly to three sources, first to decisions of the ancient judges (of whom the most distinguished was Sen, son of Aighe), given in accordance with the principles of natural justice, and handed down by tradition; secondly, to the enactments of the Triennial Parliaments, known as the Great Feis of Tara; thirdly, to the customary laws, which grew up in the course of ages and regulated the social relations of the people, according to the principles of a patriarchal society, of which the hereditary chief was the head. This great Code naturally contained many provisions that regulated the druidical rights, privileges, and worship, all of which had to be expunged. The Irish, too, were a passionate and warlike race, who rarely forgave injuries or insults, until they were atoned for according to a strict law of retaliation, which was by no means in accordance with the mild and forgiving spirit of the Gospel. In so far as the Brehon Code was founded on this principle, it was necessary for St. Patrick to abolish or amend its provisions. Moreover, the new Church claimed its own rights and privileges, for which it was important to secure formal legal sanction, and to have embodied in the great Code of the Nation. This was of itself a difficult and important task. The _Senchus Mor_ explains the motives that prompted the revision of the Brehon Code with great clearness. Dubhthach Mac Ua Lugair, the Chief Poet and Brehon of Erin, was one of the first to believe in Patrick's Gospel at Tara; and it happened to be his duty to pronounce judgment on the man who slew Odhran, Patrick's Charioteer. Thereupon Patrick and Dubhthach convoked the men of Erin to a conference at Tara, as it would seem, and Dubhthach explained all that Patrick had achieved since his arrival in Erin, and how he had overcome Laeghaire and his Druids, by the great signs and wonders which he had wrought. "Then all the men of Erin bowed down in obedience to the will of God and St. Patrick. It was then that all the professors of the sciences in Erin were assembled, and each of them exhibited his art before Patrick in the presence of every chief in Erin. It was then too that Dubhthach was ordered to exhibit the judgments, and all the poetry of Erin, and every law which prevailed amongst the men of Erin, through the law of nature, and the law of the seers, and in the judgments of the island of Erin, and in the poets," who were at first the judges.