Speaking, then, of the group generally known as a tref, we must regard it, not only as a taxable area, but also as the natural group known everywhere as a trefgordd, i.e. the natural group of the homesteads of relatives or neighbours acting together as a single community as regards their cattle and their ploughing.
The typical lawful trefgordd is thus described:—
This is the complement of a lawful trefgordd: nine houses and one plough and one oven (odyn) and one churn (gordd) and one cat and one cock and one bull and one herdsman.[32]
There is another passage which mentions the nine buildings in the tref.
These persons do not forfeit life.…
The necessitous for the theft of food after he has traversed three trevs, and nine houses in each trev, without obtaining a gift though asked for.[33]
So, in case of fire from negligence in a tref, the holder of the house in which it arose was to pay for the damage to the next houses on each side if they took fire.[34] And again no indemnity was to be paid to the owners in a trefgordd for damages from the fire of a smithy if covered with shingles or tiles or sods, nor from the fire of a bath, provided always that the smithy and the bath were at least seven fathoms from the other houses in the trefgordd.[35]
Not always of one gwely only.
The description above quoted of the normal trefgordd suggests that the herd under the one herdsman did not belong to one person or homestead, but to many; and so far it seems to be consistent with the surveys which represent the villatæ as occupied by the cattle of several family groups who had grazing rights therein.
And this, too, accords with what the Denbigh Extent tells us of the individual tribesmen, viz. that only some of them had homesteads. So-and-so ‘habet domum’ or ‘non habet domum.’[36] The young tribesman with his da thus may have joined in a common homestead with some one else—probably with his parents or near relatives.