This gradual growth of fuidhirs into sencleithe tenants in five generations of occupation is illustrated by the retention of rights for a corresponding period. In the Book of Aicill (p. 157) is a statement that the land of an imbecile person (a fool’s land) is not lost to his descendants, though they be also imbeciles, ‘till five persons:’ that is, till the fifth generation. The number of generations required does not, however, seem to have been absolutely uniform. The following is from the ‘Crith Gabhlach’ (p. 321):-- If there be service from them (cottier and fuidhir tenants which he, the chief, brings upon the land) to ‘flaith’ chiefs to nine times nine (years?), they are cottiers and fuidhir tenants; they are _sencleithe_ tenants from that out. In the Editor’s note (p. 350) to the sequel to the ‘Crith Gabhlach,’ there is a statement that the sencleithe tenant was a man who came from his natural chief to settle under another chief; and if he or his successors continued away during the time of three successive chiefs, with the knowledge of the former chief, and unclaimed by him or his successors, he or they then became ‘sencleithe,’ and could not go away of themselves nor be claimed by the other.[74] [Sidenote: Comparison with Cymric custom as to strangers, and as to the link between chief and tribesmen made by bestowal and acceptance of cattle.] These passages, taken together, seem to imply that after five, or sometimes three, generations of tenancy under the same chieftain or his successors, the fuidhir tenants became in some sense _adscripti glebæ_, like the Cymric alltuds, and at the same time formed a group of kindred very much like a Cymric gwely. Beyond this it is not easy to realise the position of the _sencleithe_ person. The text of the Brehon law tracts is often very obscure, and the commentary so imperfect that the suggestion again and again occurs to the student that the commentator may sometimes himself be groping in the dark. Moreover, all the Brehon tracts have not yet been published, so that we have as yet only part of the evidence before us. Still it seems to be safe to say that there are indications that, as in Wales, there were rungs in the social ladder by which the stranger or unfree tenant might, after a certain number of generations, climb into something like freedom and tribal rights at the cost of becoming at the same time attached to the land of the chieftain; and that to the freeman also the grades of social rank were in some measure dependent upon the social position of fathers and grandfathers and great-grandfathers as well as upon the acceptance of stock and the payment of food-rent and the performance of services to chieftains of higher rank.