Bearing in mind that they are the cherished heroes of popular fancy in Ireland and the Scottish Highlands, we have now to inquire whether they were Celtic in origin. We have seen that the Celts were a conquering people in Ireland, bringing with them their own religion and mythology, their own sagas and tales reflected now in the mythological and Cúchulainn cycles, which found a local habitation in Ireland. Cúchulainn was the hero of a saga which flourished more among the aristocratic and lettered classes than among the folk, and there are few popular tales about him. But it is among the folk that the Fionn saga has always been popular, and for every peasant who could tell a story of Cúchulainn a thousand could tell one of Fionn. Conquerors often adopt beliefs, traditions, and customs of the aboriginal folk, after hostilities have ceased, and if the pre-Celtic people had a popular hero and a saga concerning him, it is possible that in time it was accepted by the Celts or by the lower classes among them. But in the process it must have been completely Celticised, like the aborigines themselves; to its heroes were given Celtic names, or they may have been associated with existing Celtic personages like Cumal, and the whole saga was in time adapted to the conceptions and legendary history of the Celts. Thus we might account for the fact that it has so largely remained without admixture with the mythological and Cúchulainn cycles, though its heroes are brought into relation with the older gods. Thus also we might account for its popularity as compared with the Cúchulainn saga among the peasantry in whose veins must flow so much of the aboriginal blood both in Ireland and the Highlands. In other words, it was the saga of a non-Celtic people occupying both Ireland and Scotland. If Celts from Western Europe occupied the west of Scotland at an early date, they may have been so few in number that their own saga or sagas died out. Or if the Celtic occupation of the West Highlands originated first from Ireland, the Irish may have been unable to impose their Cúchulainn saga there, or if they themselves had already adopted the Fionn saga and found it again in the Highlands, they would but be the more attached to what was already localised there. This would cut the ground from the theory that the Fionn saga was brought to Scotland from Ireland, and it would account for its popularity in the Highlands, as well as for the fact that many Fionn stories are attached to Highland as well as to Irish localities, while many place-names in both countries have a Fian origin. Finally, the theory would explain the existence of so many _Märchen_ about Fionn and his men, so few about Cúchulainn.