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.