This article presents pleadings from the mid-sixteenth century, discovered by Athol Murray. They were written by Scotland’s Lord Advocate. He represented Crown and State, sat on the bench with the judges in the “College of Justice” (later known as the “Court of Session”), and was even entitled to partake and vote in their deliberations. In the present case, he acted as a pursuer in civil proceedings to disprove a forged document in order to pave the way for criminal prosecution. He submitted to the judges a mass of citations from learned literature of Roman and canon law (the so-called Jus Commune). The pleadings of this high-ranking civil servant illustrate that Jus Commune was applied in Scotland whenever a situation was not expressly regulated otherwise by national legislation or custom. Comparison to cases in Sinclair’s Practicks (1540–9)1 will additionally illustrate this.