While each tribe had its schools, these were linked together in a national system. Professors of every school were free of the island; it was the warrior's duty to protect them as they moved from court to court. An ancient tale tells how the chiefs of Emain near Armagh placed sentinels along the Gap of the North to turn back every poet who sought to leave the country and to bring on their way with honour every one who sought to enter in. There was no stagnation where competition extended over the whole island. The greatest of the teachers were given the dignity of "Professors of all the Gaels." Learned men in their degrees ranked with kings and chiefs, and high-professors sat by the high-king and shared his honours. The king, said the laws, "could by his mere word decide against every class of persons except those of the two orders of religion and learning, who are of equal value with himself."
It is in this exaltation of learning in the national life that we must look for the real significance of Irish history--the idea of a society loosely held in a political sense, but bound together in a spiritual union. The assemblies which took place in every province and every petty state were the guarantees of the national civilization. They were periodical exhibitions of everything the people esteemed--democracy, aristocracy, king-craft, literature, tradition, art, commerce, law, sport, religion, display, even rustic buffoonery. The years between one festival and another were spent in serious preparation for the next; a multitude of maxims were drawn up to direct the conduct of the people. So deeply was their importance felt that the Irish kept the tradition diligently, and even in the darkest times of their history, down to the seventeenth century, still gathered to "meetings on hills" to exercise their law and hear their learned men.
In the time of the Roman Empire, therefore, the Irish looked on themselves as one race, obedient to one law, united in one culture and belonging to one country. Their unity is symbolised by the great genealogical compilations in which all the Gaels are traced to one ancestry, and in the collections of topographical legends dealing with hundreds of places, where every nook and corner of the island is supposed to be of interest to the whole of Ireland. The tribal boundaries were limits to the material power of a chief and to that only: they were no barriers to the national thought or union. The learned man of the clan was the learned man of the Gaelic race. By all the higher matters of language and learning, of equity and history, the people of Ireland were one. A noble figure told the unity of their land within the circuit of the ocean. The Three Waves of Erin, they said, smote upon the shore with a foreboding roar when danger threatened the island; Cleena's wave called to Munster at an inlet near Cork, while Tonn Rury at Dundrum and Tonn Tuaithe at the mouth of the Bann sounded to the men of Ulster.