In the Venedotian Code used in Gwynedd, the units of length were said to have been codified by Dyfnwal Moelmud but retained unchanged by Hywel Dda. The code provided for computing the units variously, as well as deriving them from grains of barley. In measuring milk and its legal worth (teithi), disputes over the length of the inch used in the container were to be resolved by the width of the judge's thumb. The code notes that in some areas of Wales, the rod used to compute the Welsh acre (erw) was not reckoned from feet but taken to be "as long as the tallest man in the [tref], with his hand above his head".
In the Venedotian Code used in Gwynedd, the basic field unit was the Welsh acre or erw, whose legal description—its breadth as far as a man can reach in either direction with an ox-goad as long as the long yoke (16 Welsh feet) and its length "thirty times that measure"—is noted by Owen as ambiguous. He finds it more likely, however, that the "measure" to be multiplied thirty times is the width of the acre (i.e., two long yokes) rather than a single long yoke.
although in fact the commutes and cantrefs were fixed political entities with quite various sizes. The 11th-century Bleddyn ap Cynfyn is also described as having changed the legal composition of the homestead for purposes of inheritance &c., varying its size depending on the social status of the owner. The homestead of a nobleman (uchelwr) was 12 Welsh acres, that of a serf (Med. eẏllt, Mod. aillt) had 8, and that of a bondsman or slave (Med. godaẏauc) had 4. The text, however, notes the uncommonness of this division and says it was generally understood as 4 acres regardless of status.
^Roche gives this as computed the length of grains of barley rather than their width, but this does not appear anywhere in the statutes and early reckoning elsewhere was by the width or breadth of the barleycorn.
^Although note that Wade-Evans preferred 18 feet to the rod and the Latin Peniarth MS. 28 gives 16½ feet to the long yoke.
Owen, Aneurin, ed. (1841), "The Venedotian Code", Ancient Laws and Institutes of Wales; Comprising Laws Supposed to be Enacted by Howel the Good, Modified by Subsequent Regulations under the Native Princes prior to the Conquest by Edward the First: And Anomalous Laws, Consisting Principally of Institutions which by the Statute of Ruddlan were Admitted to Continue in Force: With an English Translation of the Welsh Text, to which are Added A few Latin Transcripts, Containing Digests of the Welsh Laws, Principally of the Dimetian Code, London: Commissioners on the Public Records of the Kingdom. (in Welsh) & (in English)