Ancient Laws of Ireland - Volume 1: Senchus Mor

It is obvious that the limitation to "seven" must have been gained at the cost of a little Procrustean (forcing something into a set form) violence. Indeed, the variations point to differences of opinion or practice regarding the items that make up some of these Heptads. However, the use of the formula suggests it was a relic handed down from an early period, possibly connected with the well-known septenary division of grades. The number "seven" had become, to a certain extent, consecrated by Biblical references: the seven days of creation, the seven years of jubilee, etc.

These Heptads, as far as they are intelligible, are self-explanatory, so analysis is unnecessary. The index given is arranged according to the Irish words, but the following table will probably be suggestive: