Here, then, we have the _hide_ the typical holding of a _free_ family, as the _centuria_ was under Roman law. A free Saxon thane might hold many hides, and so might and did the lord of a Roman villa hold more than one 'centuria' within its bounds. Still Columella took as his type of a Roman farm the 'centuria' of 200 acres,[617] and calculated how much seed, how many oxen, how many _opera_, or day-works of slaves, or 'coloni' were required to till it. The hide, double or single, was also a land measure, and contained eight or four yard-lands, and so also was the 'centuria' a land measure divisible into eight normal holdings allotted with single yokes. Both also became, as we have seen, units of assessment. But in England the hide was the unit. Under the Roman system of taxation the _jugum_ was the unit. [p397] This variation, however, confirms the connexion. The Roman _jugum_, or yoke of two oxen, made a complete plough. Nothing less than the hide was the complete holding in England, because a team of eight oxen was required for English ploughing. The yard-land was only a fractional holding, incomplete for purposes of ploughing without co-operation. Hence it would seem that the complete _plough_ was really the unit in both cases. «The Saxon 'hidation' and the Roman 'jugatio.'» How closely the English hidation followed the lines of the Roman '_jugatio_' has already been seen. When to the many resemblances of the hide to the 'centuria,' and of the 'jugum' to the virgate, regarded as units of assessment, are now added the other connecting links found in this chapter, in things, in figures, and in words, between the Saxon open-field system, and that of the districts of Upper Germany, so long under Roman rule, the English hidation may well be suspected to go back to Roman times, and to be possibly a survival of the Roman _jugation_. When Henry of Huntingdon, in describing the Domesday Survey, instead of saying that inquiry was made how many hides and how many virgates there were, uses the words 'quot _jugata_ et quot virgata terræ,'[618] he at any rate used the exact words which describe what in the Codex Theodosianus is spoken of as taxation 'per _jugationem_.'[619] Not, as already said, that the Romans introduced into Britain the division of land according to plough teams, and the number of oxen contributed [p398] to the plough team. It would grow, as we have seen, naturally out of tribal arrangements whenever the tribes settled and became agricultural, instead of wandering about with their herds of cattle. It was found in Wales and Ireland and Scotland, in Bohemia, apparently in Slavonic districts also and further east.[620] It is much more likely that the Romans, according to their usual custom, adopted a barbarian usage and seized upon an existing and obvious unit as the basis of provincial taxation. «Roman _tributum_ in Frisia paid in hides.»