The Molmutine Laws were the laws said to have been instituted over the Britons by Dyfnwal Moelmud,[1] who is also referred by the Latin form of his name, Dunvallo Molmutius (from which the Molmutine Laws take their title).[2] The Laws were most famously described by Geoffrey of Monmouth in his Historia Regum Britanniae.[3] Little remains known of these laws, with surviving Welsh codes simply noting that Dyfnwal's laws were largely superseded by the new codes instituted by Hywel Da.[4] Hywel was said, however, to have retained Dyfnwal's units of measurement.