Lanark becomes one of the Court of Four Burghs and is given sole custody of the  standard weight for Scotland form which all other weights were calculated.

After 1368 Lanark, as part of the Court of Four Burghs was in charge of keeping one of the Scottish standard measures, the 'stane wecht'. The burgh was responsible for the supply of accurate weights for day to day use to the rest of Scotland. These were made by local smiths and stamped with the Burghs's crest as proof of origin and certification of accuracy.