ere then committed to
writing for the first time, they could have been handed down for many
centuries orally by the Ollamhs; for no amount of literary effort could
be supposed too great for a class of men so exclusively and laboriously
devoted to learning.

As the Milesians were the last of the ancient colonists, and had subdued
the races previously existing in Ireland, only their genealogies, with a
few exceptions, have been preserved. The genealogical tree begins,
therefore, with the brothers Eber and Eremon, the two surviving leaders
of the expedition, whose ancestors are traced back to Magog, the son of
Japhet. The great southern chieftains, such as the MacCarthys and
O'Briens, claim descent from Eber; the northern families of O'Connor,
O'Donnell, and O'Neill, claim Eremon as their head. There are also other
families claiming descent from Emer, the son of Ir, brother to Eber and
Eremon; as also from their cousin Lugaidh, the son of Ith. From four
sources the principal Celtic families of Ireland have sprung; and though
they do not quite trace up the line to

"The grand old gardener and his wife,"

they have a pedigree which cannot be gainsaid, and which might be
claimed with pride by many a monarch. MacFirbis' Book of
Genealogies,[77] compiled in the year 1650, from lost records, is the
most perfect work of this kind extant. But there are tracts in the Book
of Leinster (compiled A.D. 1130), and in the Book of Ballymote (compiled
A.D. 1391), which are of the highest authority. O'Curry is of opinion,
that those in the Book of Leinster were copied from the Saltair of
Cashel and other contemporaneous works.

The historical use of these genealogies is very great, not only because
they give an authentic pedigree and approximate data for chronological
calculation, but from the immense amount of correlative information
which they contain. Every free-born man of the tribe was entitled by
_blood_, should it come to his turn, to succeed to the chieftaincy:
hence the exactitude with which each pedigree was kept; hence their
importance in the estimation of each individual; hence the incidental
matter they contain, by the mention of such historical events[78] as may
have acted on different tribes and families, by which they lost their
inheritance or independence, and consequently their claim, however
remote, to the chieftaincy.

The ancient history of a people should always be studied with care and
candour by those who,